Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

6 files changed, 1398 insertions, 0 deletions

diff --git a/tools/perf/python/counting.py b/tools/perf/python/counting.py
new file mode 100755
index 000000000..02121d2bb
--- /dev/null
+++ b/tools/perf/python/counting.py
@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# -*- python -*-
+# -*- coding: utf-8 -*-
+
+import argparse
+import perf
+
+def main(event: str):
+    evlist = perf.parse_events(event)
+
+    for evsel in evlist:
+        evsel.read_format = perf.FORMAT_TOTAL_TIME_ENABLED | perf.FORMAT_TOTAL_TIME_RUNNING
+
+    evlist.open()
+    evlist.enable()
+
+    count = 100000
+    while count > 0:
+        count -= 1
+
+    evlist.disable()
+
+    for evsel in evlist:
+        for cpu in evsel.cpus():
+            for thread in evsel.threads():
+                counts = evsel.read(cpu, thread)
+                print(f"For {evsel} val: {counts.val} enable: {counts.ena} run: {counts.run}")
+
+    evlist.close()
+
+if __name__ == '__main__':
+    ap = argparse.ArgumentParser()
+    ap.add_argument('-e', '--event', help="Events to open", default="cpu-clock,task-clock")
+    args = ap.parse_args()
+    main(args.event)
diff --git a/tools/perf/python/ilist.py b/tools/perf/python/ilist.py
new file mode 100755
index 000000000..0d757ddb4
--- /dev/null
+++ b/tools/perf/python/ilist.py
@@ -0,0 +1,515 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+"""Interactive perf list."""
+
+from abc import ABC, abstractmethod
+import argparse
+from dataclasses import dataclass
+import math
+from typing import Any, Dict, Optional, Tuple
+import perf
+from textual import on
+from textual.app import App, ComposeResult
+from textual.binding import Binding
+from textual.containers import Horizontal, HorizontalGroup, Vertical, VerticalScroll
+from textual.css.query import NoMatches
+from textual.command import SearchIcon
+from textual.screen import ModalScreen
+from textual.widgets import Button, Footer, Header, Input, Label, Sparkline, Static, Tree
+from textual.widgets.tree import TreeNode
+
+
+def get_info(info: Dict[str, str], key: str):
+    return (info[key] + "\n") if key in info else ""
+
+
+class TreeValue(ABC):
+    """Abstraction for the data of value in the tree."""
+
+    @abstractmethod
+    def name(self) -> str:
+        pass
+
+    @abstractmethod
+    def description(self) -> str:
+        pass
+
+    @abstractmethod
+    def matches(self, query: str) -> bool:
+        pass
+
+    @abstractmethod
+    def parse(self) -> perf.evlist:
+        pass
+
+    @abstractmethod
+    def value(self, evlist: perf.evlist, evsel: perf.evsel, cpu: int, thread: int) -> float:
+        pass
+
+
+@dataclass
+class Metric(TreeValue):
+    """A metric in the tree."""
+    metric_name: str
+    metric_pmu: str
+
+    def name(self) -> str:
+        return self.metric_name
+
+    def description(self) -> str:
+        """Find and format metric description."""
+        for metric in perf.metrics():
+            if metric["MetricName"] != self.metric_name:
+                continue
+            if self.metric_pmu and metric["PMU"] != self.metric_pmu:
+                continue
+            desc = get_info(metric, "BriefDescription")
+            desc += get_info(metric, "PublicDescription")
+            desc += get_info(metric, "MetricExpr")
+            desc += get_info(metric, "MetricThreshold")
+            return desc
+        return "description"
+
+    def matches(self, query: str) -> bool:
+        return query in self.metric_name
+
+    def parse(self) -> perf.evlist:
+        return perf.parse_metrics(self.metric_name, self.metric_pmu)
+
+    def value(self, evlist: perf.evlist, evsel: perf.evsel, cpu: int, thread: int) -> float:
+        try:
+            val = evlist.compute_metric(self.metric_name, cpu, thread)
+            return 0 if math.isnan(val) else val
+        except:
+            # Be tolerant of failures to compute metrics on particular CPUs/threads.
+            return 0
+
+
+@dataclass
+class PmuEvent(TreeValue):
+    """A PMU and event within the tree."""
+    pmu: str
+    event: str
+
+    def name(self) -> str:
+        if self.event.startswith(self.pmu) or ':' in self.event:
+            return self.event
+        else:
+            return f"{self.pmu}/{self.event}/"
+
+    def description(self) -> str:
+        """Find and format event description for {pmu}/{event}/."""
+        for p in perf.pmus():
+            if p.name() != self.pmu:
+                continue
+            for info in p.events():
+                if "name" not in info or info["name"] != self.event:
+                    continue
+
+                desc = get_info(info, "topic")
+                desc += get_info(info, "event_type_desc")
+                desc += get_info(info, "desc")
+                desc += get_info(info, "long_desc")
+                desc += get_info(info, "encoding_desc")
+                return desc
+        return "description"
+
+    def matches(self, query: str) -> bool:
+        return query in self.pmu or query in self.event
+
+    def parse(self) -> perf.evlist:
+        return perf.parse_events(self.name())
+
+    def value(self, evlist: perf.evlist, evsel: perf.evsel, cpu: int, thread: int) -> float:
+        return evsel.read(cpu, thread).val
+
+
+class ErrorScreen(ModalScreen[bool]):
+    """Pop up dialog for errors."""
+
+    CSS = """
+    ErrorScreen {
+        align: center middle;
+    }
+    """
+
+    def __init__(self, error: str):
+        self.error = error
+        super().__init__()
+
+    def compose(self) -> ComposeResult:
+        yield Button(f"Error: {self.error}", variant="primary", id="error")
+
+    def on_button_pressed(self, event: Button.Pressed) -> None:
+        self.dismiss(True)
+
+
+class SearchScreen(ModalScreen[str]):
+    """Pop up dialog for search."""
+
+    CSS = """
+    SearchScreen Horizontal {
+        align: center middle;
+        margin-top: 1;
+    }
+    SearchScreen Input {
+        width: 1fr;
+    }
+    """
+
+    def compose(self) -> ComposeResult:
+        yield Horizontal(SearchIcon(), Input(placeholder="Event name"))
+
+    def on_input_submitted(self, event: Input.Submitted) -> None:
+        """Handle the user pressing Enter in the input field."""
+        self.dismiss(event.value)
+
+
+class Counter(HorizontalGroup):
+    """Two labels for a CPU and its counter value."""
+
+    CSS = """
+    Label {
+        gutter: 1;
+    }
+    """
+
+    def __init__(self, cpu: int) -> None:
+        self.cpu = cpu
+        super().__init__()
+
+    def compose(self) -> ComposeResult:
+        label = f"cpu{self.cpu}" if self.cpu >= 0 else "total"
+        yield Label(label + " ")
+        yield Label("0", id=f"counter_{label}")
+
+
+class CounterSparkline(HorizontalGroup):
+    """A Sparkline for a performance counter."""
+
+    def __init__(self, cpu: int) -> None:
+        self.cpu = cpu
+        super().__init__()
+
+    def compose(self) -> ComposeResult:
+        label = f"cpu{self.cpu}" if self.cpu >= 0 else "total"
+        yield Label(label)
+        yield Sparkline([], summary_function=max, id=f"sparkline_{label}")
+
+
+class IListApp(App):
+    TITLE = "Interactive Perf List"
+
+    BINDINGS = [
+        Binding(key="s", action="search", description="Search",
+                tooltip="Search events and PMUs"),
+        Binding(key="n", action="next", description="Next",
+                tooltip="Next search result or item"),
+        Binding(key="p", action="prev", description="Previous",
+                tooltip="Previous search result or item"),
+        Binding(key="c", action="collapse", description="Collapse",
+                tooltip="Collapse the current PMU"),
+        Binding(key="^q", action="quit", description="Quit",
+                tooltip="Quit the app"),
+    ]
+
+    CSS = """
+        /* Make the 'total' sparkline a different color. */
+        #sparkline_total > .sparkline--min-color {
+            color: $accent;
+        }
+        #sparkline_total > .sparkline--max-color {
+            color: $accent 30%;
+        }
+        /*
+         * Make the active_search initially not displayed with the text in
+         * the middle of the line.
+         */
+        #active_search {
+            display: none;
+            width: 100%;
+            text-align: center;
+        }
+    """
+
+    def __init__(self, interval: float) -> None:
+        self.interval = interval
+        self.evlist = None
+        self.selected: Optional[TreeValue] = None
+        self.search_results: list[TreeNode[TreeValue]] = []
+        self.cur_search_result: TreeNode[TreeValue] | None = None
+        super().__init__()
+
+    def expand_and_select(self, node: TreeNode[Any]) -> None:
+        """Expand select a node in the tree."""
+        if node.parent:
+            node.parent.expand()
+            if node.parent.parent:
+                node.parent.parent.expand()
+        node.expand()
+        node.tree.select_node(node)
+        node.tree.scroll_to_node(node)
+
+    def set_searched_tree_node(self, previous: bool) -> None:
+        """Set the cur_search_result node to either the next or previous."""
+        l = len(self.search_results)
+
+        if l < 1:
+            tree: Tree[TreeValue] = self.query_one("#root", Tree)
+            if previous:
+                tree.action_cursor_up()
+            else:
+                tree.action_cursor_down()
+            return
+
+        if self.cur_search_result:
+            idx = self.search_results.index(self.cur_search_result)
+            if previous:
+                idx = idx - 1 if idx > 0 else l - 1
+            else:
+                idx = idx + 1 if idx < l - 1 else 0
+        else:
+            idx = l - 1 if previous else 0
+
+        node = self.search_results[idx]
+        if node == self.cur_search_result:
+            return
+
+        self.cur_search_result = node
+        self.expand_and_select(node)
+
+    def action_search(self) -> None:
+        """Search was chosen."""
+        def set_initial_focus(event: str | None) -> None:
+            """Sets the focus after the SearchScreen is dismissed."""
+
+            search_label = self.query_one("#active_search", Label)
+            search_label.display = True if event else False
+            if not event:
+                return
+            event = event.lower()
+            search_label.update(f'Searching for events matching "{event}"')
+
+            tree: Tree[str] = self.query_one("#root", Tree)
+
+            def find_search_results(event: str, node: TreeNode[str],
+                                    cursor_seen: bool = False,
+                                    match_after_cursor: Optional[TreeNode[str]] = None
+                                    ) -> Tuple[bool, Optional[TreeNode[str]]]:
+                """Find nodes that match the search remembering the one after the cursor."""
+                if not cursor_seen and node == tree.cursor_node:
+                    cursor_seen = True
+                if node.data and node.data.matches(event):
+                    if cursor_seen and not match_after_cursor:
+                        match_after_cursor = node
+                    self.search_results.append(node)
+
+                if node.children:
+                    for child in node.children:
+                        (cursor_seen, match_after_cursor) = \
+                            find_search_results(event, child, cursor_seen, match_after_cursor)
+                return (cursor_seen, match_after_cursor)
+
+            self.search_results.clear()
+            (_, self.cur_search_result) = find_search_results(event, tree.root)
+            if len(self.search_results) < 1:
+                self.push_screen(ErrorScreen(f"Failed to find pmu/event or metric {event}"))
+                search_label.display = False
+            elif self.cur_search_result:
+                self.expand_and_select(self.cur_search_result)
+            else:
+                self.set_searched_tree_node(previous=False)
+
+        self.push_screen(SearchScreen(), set_initial_focus)
+
+    def action_next(self) -> None:
+        """Next was chosen."""
+        self.set_searched_tree_node(previous=False)
+
+    def action_prev(self) -> None:
+        """Previous was chosen."""
+        self.set_searched_tree_node(previous=True)
+
+    def action_collapse(self) -> None:
+        """Collapse the part of the tree currently on."""
+        tree: Tree[str] = self.query_one("#root", Tree)
+        node = tree.cursor_node
+        if node and node.parent:
+            node.parent.collapse_all()
+            node.tree.scroll_to_node(node.parent)
+
+    def update_counts(self) -> None:
+        """Called every interval to update counts."""
+        if not self.selected or not self.evlist:
+            return
+
+        def update_count(cpu: int, count: int):
+            # Update the raw count display.
+            counter: Label = self.query(f"#counter_cpu{cpu}" if cpu >= 0 else "#counter_total")
+            if not counter:
+                return
+            counter = counter.first(Label)
+            counter.update(str(count))
+
+            # Update the sparkline.
+            line: Sparkline = self.query(f"#sparkline_cpu{cpu}" if cpu >= 0 else "#sparkline_total")
+            if not line:
+                return
+            line = line.first(Sparkline)
+            # If there are more events than the width, remove the front event.
+            if len(line.data) > line.size.width:
+                line.data.pop(0)
+            line.data.append(count)
+            line.mutate_reactive(Sparkline.data)
+
+        # Update the total and each CPU counts, assume there's just 1 evsel.
+        total = 0
+        self.evlist.disable()
+        for evsel in self.evlist:
+            for cpu in evsel.cpus():
+                aggr = 0
+                for thread in evsel.threads():
+                    aggr += self.selected.value(self.evlist, evsel, cpu, thread)
+                update_count(cpu, aggr)
+                total += aggr
+        update_count(-1, total)
+        self.evlist.enable()
+
+    def on_mount(self) -> None:
+        """When App starts set up periodic event updating."""
+        self.update_counts()
+        self.set_interval(self.interval, self.update_counts)
+
+    def set_selected(self, value: TreeValue) -> None:
+        """Updates the event/description and starts the counters."""
+        try:
+            label_name = self.query_one("#event_name", Label)
+            event_description = self.query_one("#event_description", Static)
+            lines = self.query_one("#lines")
+        except NoMatches:
+            # A race with rendering, ignore the update as we can't
+            # mount the assumed output widgets.
+            return
+
+        self.selected = value
+
+        # Remove previous event information.
+        if self.evlist:
+            self.evlist.disable()
+            self.evlist.close()
+            old_lines = self.query(CounterSparkline)
+            for line in old_lines:
+                line.remove()
+            old_counters = self.query(Counter)
+            for counter in old_counters:
+                counter.remove()
+
+        # Update event/metric text and description.
+        label_name.update(value.name())
+        event_description.update(value.description())
+
+        # Open the event.
+        try:
+            self.evlist = value.parse()
+            if self.evlist:
+                self.evlist.open()
+                self.evlist.enable()
+        except:
+            self.evlist = None
+
+        if not self.evlist:
+            self.push_screen(ErrorScreen(f"Failed to open {value.name()}"))
+            return
+
+        # Add spark lines for all the CPUs. Note, must be done after
+        # open so that the evlist CPUs have been computed by propagate
+        # maps.
+        line = CounterSparkline(cpu=-1)
+        lines.mount(line)
+        for cpu in self.evlist.all_cpus():
+            line = CounterSparkline(cpu)
+            lines.mount(line)
+        line = Counter(cpu=-1)
+        lines.mount(line)
+        for cpu in self.evlist.all_cpus():
+            line = Counter(cpu)
+            lines.mount(line)
+
+    def compose(self) -> ComposeResult:
+        """Draws the app."""
+        def metric_event_tree() -> Tree:
+            """Create tree of PMUs and metricgroups with events or metrics under."""
+            tree: Tree[TreeValue] = Tree("Root", id="root")
+            pmus = tree.root.add("PMUs")
+            for pmu in perf.pmus():
+                pmu_name = pmu.name().lower()
+                pmu_node = pmus.add(pmu_name)
+                try:
+                    for event in sorted(pmu.events(), key=lambda x: x["name"]):
+                        if "deprecated" in event:
+                            continue
+                        if "name" in event:
+                            e = event["name"].lower()
+                            if "alias" in event:
+                                pmu_node.add_leaf(f'{e} ({event["alias"]})',
+                                                  data=PmuEvent(pmu_name, e))
+                            else:
+                                pmu_node.add_leaf(e, data=PmuEvent(pmu_name, e))
+                except:
+                    # Reading events may fail with EPERM, ignore.
+                    pass
+            metrics = tree.root.add("Metrics")
+            groups = set()
+            for metric in perf.metrics():
+                groups.update(metric["MetricGroup"])
+
+            def add_metrics_to_tree(node: TreeNode[TreeValue], parent: str, pmu: str = None):
+                for metric in sorted(perf.metrics(), key=lambda x: x["MetricName"]):
+                    metric_pmu = metric.get('PMU')
+                    if pmu and metric_pmu and metric_pmu != pmu:
+                        continue
+                    if parent in metric["MetricGroup"]:
+                        name = metric["MetricName"]
+                        display_name = name
+                        if metric_pmu:
+                            display_name += f" ({metric_pmu})"
+                        node.add_leaf(display_name, data=Metric(name, metric_pmu))
+                        child_group_name = f'{name}_group'
+                        if child_group_name in groups:
+                            display_child_group_name = child_group_name
+                            if metric_pmu:
+                                display_child_group_name += f" ({metric_pmu})"
+                            add_metrics_to_tree(node.add(display_child_group_name),
+                                                child_group_name,
+                                                metric_pmu)
+
+            for group in sorted(groups):
+                if group.endswith('_group'):
+                    continue
+                add_metrics_to_tree(metrics.add(group), group)
+
+            tree.root.expand()
+            return tree
+
+        yield Header(id="header")
+        yield Horizontal(Vertical(metric_event_tree(), id="events"),
+                         Vertical(Label("event name", id="event_name"),
+                                  Static("description", markup=False, id="event_description"),
+                                  ))
+        yield Label(id="active_search")
+        yield VerticalScroll(id="lines")
+        yield Footer(id="footer")
+
+    @on(Tree.NodeSelected)
+    def on_tree_node_selected(self, event: Tree.NodeSelected[TreeValue]) -> None:
+        """Called when a tree node is selected, selecting the event."""
+        if event.node.data:
+            self.set_selected(event.node.data)
+
+
+if __name__ == "__main__":
+    ap = argparse.ArgumentParser()
+    ap.add_argument('-I', '--interval', help="Counter update interval in seconds", default=0.1)
+    args = ap.parse_args()
+    app = IListApp(float(args.interval))
+    app.run()
diff --git a/tools/perf/python/perf.pyi b/tools/perf/python/perf.pyi
new file mode 100644
index 000000000..58b0b3ed8
--- /dev/null
+++ b/tools/perf/python/perf.pyi
@@ -0,0 +1,672 @@
+"""Type stubs for the perf Python module."""
+from typing import Callable, Dict, List, Optional, Any, Iterator, Union
+
+def config_get(name: str) -> Optional[str]:
+    """Get a configuration value from perf config.
+
+    Args:
+        name: The configuration variable name (e.g., 'colors.top').
+
+    Returns:
+        The configuration value as a string, or None if not set.
+    """
+    ...
+
+def metrics() -> List[Dict[str, Union[str, List[str]]]]:
+    """Get a list of available metrics.
+
+    Returns:
+        A list of dictionaries, each describing a metric.
+    """
+    ...
+
+def syscall_name(id: int, *, elf_machine: Optional[int] = None) -> str:
+    """Convert a syscall number to its name.
+
+    Args:
+        sc_id: The syscall number.
+        elf_machine: Optional ELF machine type.
+
+    Returns:
+        The name of the syscall.
+    """
+    ...
+
+def syscall_id(name: str, *, elf_machine: Optional[int] = None) -> int:
+    """Convert a syscall name to its number.
+
+    Args:
+        name: The syscall name.
+        elf_machine: Optional ELF machine type.
+
+    Returns:
+        The number of the syscall.
+    """
+    ...
+
+def parse_events(
+    event_string: str,
+    cpus: Optional[cpu_map] = None,
+    threads: Optional['thread_map'] = None
+) -> 'evlist':
+    """Parse an event string and return an evlist.
+
+    Args:
+        event_string: The event string (e.g., 'cycles,instructions').
+        cpus: Optional CPU map to bind events to.
+        threads: Optional thread map to bind events to.
+
+    Returns:
+        An evlist containing the parsed events.
+    """
+    ...
+
+def parse_metrics(
+    metrics_string: str,
+    pmu: Optional[str] = None,
+    cpus: Optional[cpu_map] = None,
+    threads: Optional['thread_map'] = None
+) -> 'evlist':
+    """Parse a string of metrics or metric groups and return an evlist."""
+    ...
+
+def tracepoint(sys: str, name: str) -> int:
+    """Returns the tracepoint ID for a given system and name."""
+    ...
+
+def pmus() -> Iterator[Any]:
+    """Returns a sequence of pmus."""
+    ...
+
+class data:
+    """Represents a perf data file."""
+    def __init__(self, path: str = ..., fd: int = ...) -> None: ...
+
+class thread:
+    """Represents a thread in the system."""
+    def comm(self) -> str:
+        """Get the command name of the thread."""
+        ...
+    pid: int
+    tid: int
+    ppid: int
+    cpu: int
+
+class counts_values:
+    """Raw counter values."""
+    id: int
+    val: int
+    ena: int
+    run: int
+    lost: int
+    values: List[int]
+
+class thread_map:
+    """Map of threads being monitored."""
+    def __init__(self, pid: int = -1, tid: int = -1) -> None:
+        """Initialize a thread map.
+
+        Args:
+            pid: Process ID to monitor (-1 for all).
+            tid: Thread ID to monitor (-1 for all).
+        """
+        ...
+    def __len__(self) -> int: ...
+    def __getitem__(self, index: int) -> int: ...
+    def __iter__(self) -> Iterator[int]: ...
+
+class evsel:
+    """Event selector, represents a single event being monitored."""
+    def __init__(
+        self,
+        type: int = ...,
+        config: int = ...,
+        sample_freq: int = ...,
+        sample_period: int = ...,
+        sample_type: int = ...,
+        read_format: int = ...,
+        disabled: bool = ...,
+        inherit: bool = ...,
+        pinned: bool = ...,
+        exclusive: bool = ...,
+        exclude_user: bool = ...,
+        exclude_kernel: bool = ...,
+        exclude_hv: bool = ...,
+        exclude_idle: bool = ...,
+        mmap: bool = ...,
+        context_switch: bool = ...,
+        comm: bool = ...,
+        freq: bool = ...,
+        inherit_stat: bool = ...,
+        enable_on_exec: bool = ...,
+        task: bool = ...,
+        watermark: int = ...,
+        precise_ip: int = ...,
+        mmap_data: bool = ...,
+        sample_id_all: bool = ...,
+        wakeup_events: int = ...,
+        bp_type: int = ...,
+        bp_addr: int = ...,
+        bp_len: int = ...,
+        idx: int = ...,
+    ) -> None: ...
+    def __str__(self) -> str:
+        """Return string representation of the event."""
+        ...
+    def open(self) -> None:
+        """Open the event selector file descriptor table."""
+        ...
+    def read(self, cpu: int, thread: int) -> counts_values:
+        """Read counter values for a specific CPU and thread."""
+        ...
+    ids: List[int]
+    def cpus(self) -> cpu_map:
+        """Get CPU map for this event."""
+        ...
+    def threads(self) -> thread_map:
+        """Get thread map for this event."""
+        ...
+    tracking: bool
+    config: int
+    read_format: int
+    sample_period: int
+    sample_type: int
+    size: int
+    type: int
+    wakeup_events: int
+
+
+class _sample_members:
+    sample_pid: int
+    sample_tid: int
+    sample_time: int
+    sample_id: int
+    sample_stream_id: int
+    sample_period: int
+    sample_cpu: int
+
+class sample_event(_sample_members):
+    """Represents a sample event from perf."""
+    evsel: evsel
+    sample_ip: int
+    sample_addr: int
+    sample_phys_addr: int
+    sample_weight: int
+    sample_data_src: int
+    sample_insn_count: int
+    sample_cyc_count: int
+    type: int
+    raw_buf: bytes
+    dso: str
+    dso_long_name: str
+    dso_bid: Optional[bytes]
+    map_start: int
+    map_end: int
+    map_pgoff: int
+    symbol: str
+    sym_start: int
+    sym_end: int
+    brstack: Optional['branch_stack']
+    callchain: Optional['callchain']
+    def srccode(self) -> str: ...
+    def insn(self) -> str: ...
+    def __getattr__(self, name: str) -> Any: ...
+
+class mmap_event(_sample_members):
+    """Represents a mmap event from perf."""
+    type: int
+    misc: int
+    pid: int
+    tid: int
+    start: int
+    len: int
+    pgoff: int
+    filename: str
+    evsel: Optional['evsel']
+
+class mmap2_event(_sample_members):
+    """Represents a mmap2 event from perf."""
+    type: int
+    misc: int
+    pid: int
+    tid: int
+    start: int
+    len: int
+    pgoff: int
+    prot: int
+    flags: int
+    filename: str
+    maj: Optional[int]
+    min: Optional[int]
+    ino: Optional[int]
+    ino_generation: Optional[int]
+    build_id: Optional[bytes]
+    evsel: Optional['evsel']
+
+class lost_event(_sample_members):
+    """Represents a lost events record."""
+    type: int
+    id: int
+    lost: int
+    evsel: Optional['evsel']
+
+class comm_event(_sample_members):
+    """Represents a COMM record."""
+    type: int
+    pid: int
+    tid: int
+    comm: str
+    evsel: Optional['evsel']
+
+class task_event(_sample_members):
+    """Represents an EXIT or FORK record."""
+    type: int
+    pid: int
+    ppid: int
+    tid: int
+    ptid: int
+    time: int
+    evsel: Optional['evsel']
+
+class throttle_event(_sample_members):
+    """Represents a THROTTLE or UNTHROTTLE record."""
+    type: int
+    time: int
+    id: int
+    stream_id: int
+    evsel: Optional['evsel']
+
+class read_event(_sample_members):
+    """Represents a READ record."""
+    type: int
+    pid: int
+    tid: int
+    evsel: Optional['evsel']
+
+class switch_event(_sample_members):
+    """Represents a SWITCH or SWITCH_CPU_WIDE record."""
+    type: int
+    next_prev_pid: int
+    next_prev_tid: int
+    evsel: Optional['evsel']
+
+class branch_entry:
+    """Represents a branch entry in the branch stack.
+
+    Attributes:
+        from_ip: Source address of the branch (corresponds to 'from' keyword in C).
+        to_ip: Destination address of the branch.
+        mispred: True if the branch was mispredicted.
+        predicted: True if the branch was predicted.
+        in_tx: True if the branch was in a transaction.
+        abort: True if the branch was an abort.
+        cycles: Number of cycles since the last branch.
+        type: Type of branch.
+    """
+    from_ip: int
+    to_ip: int
+    mispred: bool
+    predicted: bool
+    in_tx: bool
+    abort: bool
+    cycles: int
+    type: int
+
+class branch_stack:
+    """Sequence of branch entries in the branch stack."""
+    def __len__(self) -> int: ...
+    def __getitem__(self, index: int) -> branch_entry: ...
+
+class callchain_node:
+    """Represents a frame in the callchain."""
+    ip: int
+    symbol: Optional[str]
+    dso: Optional[str]
+
+class callchain:
+    """Sequence of callchain frames."""
+    def __len__(self) -> int: ...
+    def __getitem__(self, index: int) -> callchain_node: ...
+
+class stat_event(_sample_members):
+    """Represents a stat event from perf."""
+    type: int
+    id: int
+    cpu: int
+    thread: int
+    val: int
+    ena: int
+    run: int
+    evsel: Optional['evsel']
+
+class stat_round_event(_sample_members):
+    """Represents a stat round event from perf."""
+    type: int
+    time: int
+    stat_round_type: int
+    evsel: Optional['evsel']
+
+class cpu_map:
+    """Map of CPUs being monitored."""
+    def __init__(self, cpustr: Optional[str] = None) -> None: ...
+    def __len__(self) -> int: ...
+    def __getitem__(self, index: int) -> int: ...
+    def __iter__(self) -> Iterator[int]: ...
+
+
+class evlist:
+    def __init__(self, cpus: cpu_map, threads: thread_map) -> None: ...
+    def open(self) -> None:
+        """Open the events in the list."""
+        ...
+    def close(self) -> None:
+        """Close the events in the list."""
+        ...
+    def mmap(self) -> None:
+        """Memory map the event buffers."""
+        ...
+    def poll(self, timeout: int) -> int:
+        """Poll for events.
+
+        Args:
+            timeout: Timeout in milliseconds.
+
+        Returns:
+            Number of events ready.
+        """
+        ...
+    def read_on_cpu(self, cpu: int) -> Optional[Any]:
+        """Read a sample event from a specific CPU.
+
+        Args:
+            cpu: The CPU number.
+
+        Returns:
+            A sample_event or other event type if available, or None.
+        """
+        ...
+    def all_cpus(self) -> cpu_map:
+        """Get a cpu_map of all CPUs in the system."""
+        ...
+    def metrics(self) -> List[str]:
+        """Get a list of metric names within the evlist."""
+        ...
+    def compute_metric(self, metric: str, cpu: int, thread: int) -> float:
+        """Compute metric for given name, cpu and thread.
+
+        Args:
+            metric: The metric name.
+            cpu: The CPU number.
+            thread: The thread ID.
+
+        Returns:
+            The computed metric value.
+        """
+        ...
+    def config(self) -> None:
+        """Configure the events in the list."""
+        ...
+    def disable(self) -> None:
+        """Disable all events in the list."""
+        ...
+    def enable(self) -> None:
+        """Enable all events in the list."""
+        ...
+    def get_pollfd(self) -> List[int]:
+        """Get a list of file descriptors for polling."""
+        ...
+    def add(self, evsel: evsel) -> int:
+        """Add an event to the list."""
+        ...
+    def __iter__(self) -> Iterator[evsel]:
+        """Iterate over the events (evsel) in the list."""
+        ...
+
+
+class session:
+    def __init__(
+        self,
+        data: data,
+        sample: Optional[Callable[[sample_event], None]] = None,
+        stat: Optional[Callable[[Any, Optional[str]], None]] = None
+    ) -> None:
+        """Initialize a perf session.
+
+        Args:
+            data: The perf data file to read.
+            sample: Callback for sample events.
+            stat: Callback for stat events.
+        """
+        ...
+    def process_events(self) -> None:
+        """Process all events in the session."""
+        ...
+    def find_thread(self, pid: int) -> thread:
+        """Returns the thread associated with a pid."""
+        ...
+
+# Event Types
+TYPE_HARDWARE: int
+"""Hardware event."""
+
+TYPE_SOFTWARE: int
+"""Software event."""
+
+TYPE_TRACEPOINT: int
+"""Tracepoint event."""
+
+TYPE_HW_CACHE: int
+"""Hardware cache event."""
+
+TYPE_RAW: int
+"""Raw hardware event."""
+
+TYPE_BREAKPOINT: int
+"""Breakpoint event."""
+
+
+# Hardware Counters
+COUNT_HW_CPU_CYCLES: int
+"""Total cycles. Be wary of what happens during CPU frequency scaling."""
+
+COUNT_HW_INSTRUCTIONS: int
+"""Retired instructions. Be careful, these can be affected by various issues,
+most notably hardware interrupt counts."""
+
+COUNT_HW_CACHE_REFERENCES: int
+"""Cache accesses. Usually this indicates Last Level Cache accesses but this
+may vary depending on your CPU."""
+
+COUNT_HW_CACHE_MISSES: int
+"""Cache misses. Usually this indicates Last Level Cache misses."""
+
+COUNT_HW_BRANCH_INSTRUCTIONS: int
+"""Retired branch instructions."""
+
+COUNT_HW_BRANCH_MISSES: int
+"""Mispredicted branch instructions."""
+
+COUNT_HW_BUS_CYCLES: int
+"""Bus cycles, which can be different from total cycles."""
+
+COUNT_HW_STALLED_CYCLES_FRONTEND: int
+"""Stalled cycles during issue [This event is an alias of idle-cycles-frontend]."""
+
+COUNT_HW_STALLED_CYCLES_BACKEND: int
+"""Stalled cycles during retirement [This event is an alias of idle-cycles-backend]."""
+
+COUNT_HW_REF_CPU_CYCLES: int
+"""Total cycles; not affected by CPU frequency scaling."""
+
+
+# Cache Counters
+COUNT_HW_CACHE_L1D: int
+"""Level 1 data cache."""
+
+COUNT_HW_CACHE_L1I: int
+"""Level 1 instruction cache."""
+
+COUNT_HW_CACHE_LL: int
+"""Last Level Cache."""
+
+COUNT_HW_CACHE_DTLB: int
+"""Data TLB."""
+
+COUNT_HW_CACHE_ITLB: int
+"""Instruction TLB."""
+
+COUNT_HW_CACHE_BPU: int
+"""Branch Processing Unit."""
+
+COUNT_HW_CACHE_OP_READ: int
+"""Read accesses."""
+
+COUNT_HW_CACHE_OP_WRITE: int
+"""Write accesses."""
+
+COUNT_HW_CACHE_OP_PREFETCH: int
+"""Prefetch accesses."""
+
+COUNT_HW_CACHE_RESULT_ACCESS: int
+"""Accesses."""
+
+COUNT_HW_CACHE_RESULT_MISS: int
+"""Misses."""
+
+
+# Software Counters
+COUNT_SW_CPU_CLOCK: int
+"""CPU clock event."""
+
+COUNT_SW_TASK_CLOCK: int
+"""Task clock event."""
+
+COUNT_SW_PAGE_FAULTS: int
+"""Page faults."""
+
+COUNT_SW_CONTEXT_SWITCHES: int
+"""Context switches."""
+
+COUNT_SW_CPU_MIGRATIONS: int
+"""CPU migrations."""
+
+COUNT_SW_PAGE_FAULTS_MIN: int
+"""Minor page faults."""
+
+COUNT_SW_PAGE_FAULTS_MAJ: int
+"""Major page faults."""
+
+COUNT_SW_ALIGNMENT_FAULTS: int
+"""Alignment faults."""
+
+COUNT_SW_EMULATION_FAULTS: int
+"""Emulation faults."""
+
+COUNT_SW_DUMMY: int
+"""Dummy event."""
+
+
+# Sample Fields
+SAMPLE_IP: int
+"""Instruction pointer."""
+
+SAMPLE_TID: int
+"""Process and thread ID."""
+
+SAMPLE_TIME: int
+"""Timestamp."""
+
+SAMPLE_ADDR: int
+"""Sampled address."""
+
+SAMPLE_READ: int
+"""Read barcode."""
+
+SAMPLE_CALLCHAIN: int
+"""Call chain."""
+
+SAMPLE_ID: int
+"""Unique ID."""
+
+SAMPLE_CPU: int
+"""CPU number."""
+
+SAMPLE_PERIOD: int
+"""Sample period."""
+
+SAMPLE_STREAM_ID: int
+"""Stream ID."""
+
+SAMPLE_RAW: int
+"""Raw sample."""
+
+
+# Format Fields
+FORMAT_TOTAL_TIME_ENABLED: int
+"""Total time enabled."""
+
+FORMAT_TOTAL_TIME_RUNNING: int
+"""Total time running."""
+
+FORMAT_ID: int
+"""Event ID."""
+
+FORMAT_GROUP: int
+"""Event group."""
+
+
+# Record Types
+RECORD_MMAP: int
+"""MMAP record. Contains header, pid, tid, addr, len, pgoff, filename, and sample_id."""
+
+RECORD_LOST: int
+"""Lost events record. Contains header, id, lost count, and sample_id."""
+
+RECORD_COMM: int
+"""COMM record. Contains header, pid, tid, comm, and sample_id."""
+
+RECORD_EXIT: int
+"""EXIT record. Contains header, pid, ppid, tid, ptid, time, and sample_id."""
+
+RECORD_THROTTLE: int
+"""THROTTLE record. Contains header, time, id, stream_id, and sample_id."""
+
+RECORD_UNTHROTTLE: int
+"""UNTHROTTLE record. Contains header, time, id, stream_id, and sample_id."""
+
+RECORD_FORK: int
+"""FORK record. Contains header, pid, ppid, tid, ptid, time, and sample_id."""
+
+RECORD_READ: int
+"""READ record. Contains header, and read values."""
+
+RECORD_SAMPLE: int
+"""SAMPLE record. Contains header, and sample data requested by sample_type."""
+
+RECORD_MMAP2: int
+"""MMAP2 record. Contains header, pid, tid, addr, len, pgoff, maj, min, ino,
+ino_generation, prot, flags, filename, and sample_id."""
+
+RECORD_AUX: int
+"""AUX record. Contains header, aux_offset, aux_size, flags, and sample_id."""
+
+RECORD_ITRACE_START: int
+"""ITRACE_START record. Contains header, pid, tid, and sample_id."""
+
+RECORD_LOST_SAMPLES: int
+"""LOST_SAMPLES record. Contains header, lost count, and sample_id."""
+
+RECORD_SWITCH: int
+"""SWITCH record. Contains header, and sample_id."""
+
+RECORD_SWITCH_CPU_WIDE: int
+"""SWITCH_CPU_WIDE record. Contains header, and sample_id."""
+
+RECORD_STAT: int
+"""STAT record."""
+
+RECORD_STAT_ROUND: int
+"""STAT_ROUND record."""
+
+RECORD_MISC_SWITCH_OUT: int
+"""MISC_SWITCH_OUT record."""
diff --git a/tools/perf/python/perf_live.py b/tools/perf/python/perf_live.py
new file mode 100755
index 000000000..616b5f657
--- /dev/null
+++ b/tools/perf/python/perf_live.py
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: GPL-2.0
+"""
+Live event session helper using perf.evlist.
+
+This module provides a LiveSession class that allows running a callback
+for each event collected live from the system, similar to perf.session
+but without requiring a perf.data file.
+"""
+
+import perf
+
+
+class LiveSession:
+    """Represents a live event collection session."""
+
+    def __init__(self, event_string: str, sample_callback):
+        self.event_string = event_string
+        self.sample_callback = sample_callback
+        # Create a cpu map for all online CPUs
+        self.cpus = perf.cpu_map()
+        # Parse events and set maps
+        self.evlist = perf.parse_events(self.event_string, self.cpus)
+        self.evlist.config()
+
+    def run(self):
+        """Run the live session."""
+        try:
+            self.evlist.open()
+            self.evlist.mmap()
+            self.evlist.enable()
+
+            while True:
+                # Poll for events with 100ms timeout
+                try:
+                    self.evlist.poll(100)
+                except InterruptedError:
+                    continue
+                for cpu in self.cpus:
+                    for _ in range(1000): # Limit to 1000 events per CPU per poll to prevent starvation
+                        try:
+                            event = self.evlist.read_on_cpu(cpu)
+                        except TypeError as e:
+                            if "Unknown CPU" in str(e):
+                                # CPU might be unmapped or offline, wait for mmap event
+                                break
+                            if "Unexpected header type" in str(e):
+                                # Ignore valid but unsupported event types
+                                continue
+                            raise
+
+                        if event is None:
+                            break
+
+                        if event.type == perf.RECORD_SAMPLE:
+                            self.sample_callback(event)
+        except KeyboardInterrupt:
+            pass
+        finally:
+            self.evlist.close()
diff --git a/tools/perf/python/tracepoint.py b/tools/perf/python/tracepoint.py
new file mode 100755
index 000000000..15b0c8268
--- /dev/null
+++ b/tools/perf/python/tracepoint.py
@@ -0,0 +1,55 @@
+#! /usr/bin/env python
+# SPDX-License-Identifier: GPL-2.0
+# -*- python -*-
+# -*- coding: utf-8 -*-
+
+import perf
+
+def change_proctitle():
+    try:
+        import setproctitle
+        setproctitle.setproctitle("tracepoint.py")
+    except:
+        print("Install the setproctitle python package to help with top and friends")
+
+def main():
+    change_proctitle()
+    cpus    = perf.cpu_map()
+    threads = perf.thread_map(-1)
+    evlist = perf.parse_events("sched:sched_switch", cpus, threads)
+    # Disable tracking of mmaps and similar that are unnecessary.
+    for ev in evlist:
+        ev.tracking = False
+    # Configure evsels with default record options.
+    evlist.config()
+    # Simplify the sample_type and read_format of evsels
+    for ev in evlist:
+        ev.sample_type = ev.sample_type & ~perf.SAMPLE_IP
+        ev.read_format = 0
+
+    evlist.open()
+    evlist.mmap()
+    evlist.enable();
+
+    while True:
+        evlist.poll(timeout = -1)
+        for cpu in cpus:
+            event = evlist.read_on_cpu(cpu)
+            if not event:
+                continue
+
+            if not isinstance(event, perf.sample_event):
+                continue
+
+            print("time %u prev_comm=%s prev_pid=%d prev_prio=%d prev_state=0x%x ==> next_comm=%s next_pid=%d next_prio=%d" % (
+                   event.sample_time,
+                   event.prev_comm,
+                   event.prev_pid,
+                   event.prev_prio,
+                   event.prev_state,
+                   event.next_comm,
+                   event.next_pid,
+                   event.next_prio))
+
+if __name__ == '__main__':
+    main()
diff --git a/tools/perf/python/twatch.py b/tools/perf/python/twatch.py
new file mode 100755
index 000000000..04f3db29b
--- /dev/null
+++ b/tools/perf/python/twatch.py
@@ -0,0 +1,61 @@
+#! /usr/bin/env python
+# SPDX-License-Identifier: GPL-2.0-only
+# -*- python -*-
+# -*- coding: utf-8 -*-
+#   twatch - Experimental use of the perf python interface
+#   Copyright (C) 2011 Arnaldo Carvalho de Melo <acme@redhat.com>
+#
+
+import perf
+
+def main(context_switch = 0, thread = -1):
+	cpus = perf.cpu_map()
+	threads = perf.thread_map(thread)
+	evsel = perf.evsel(type	  = perf.TYPE_SOFTWARE,
+			   config = perf.COUNT_SW_DUMMY,
+			   task = 1, comm = 1, mmap = 0, freq = 0,
+			   wakeup_events = 1, watermark = 1,
+			   sample_id_all = 1, context_switch = context_switch,
+			   sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU)
+
+	"""What we want are just the PERF_RECORD_ lifetime events for threads,
+	 using the default, PERF_TYPE_HARDWARE + PERF_COUNT_HW_CYCLES & freq=1
+	 (the default), makes perf reenable irq_vectors:local_timer_entry, when
+	 disabling nohz, not good for some use cases where all we want is to get
+	 threads comes and goes... So use (perf.TYPE_SOFTWARE, perf_COUNT_SW_DUMMY,
+	 freq=0) instead."""
+
+	evsel.open(cpus = cpus, threads = threads);
+	evlist = perf.evlist(cpus, threads)
+	evlist.add(evsel)
+	evlist.mmap()
+	while True:
+		evlist.poll(timeout = -1)
+		for cpu in cpus:
+			event = evlist.read_on_cpu(cpu)
+			if not event:
+				continue
+			print("cpu: {0}, pid: {1}, tid: {2} {3}".format(event.sample_cpu,
+                                                                        event.sample_pid,
+                                                                        event.sample_tid,
+                                                                        event))
+
+if __name__ == '__main__':
+    """
+	To test the PERF_RECORD_SWITCH record, pick a pid and replace
+	in the following line.
+
+	Example output:
+
+cpu: 3, pid: 31463, tid: 31593 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31593, switch_out: 1 }
+cpu: 1, pid: 31463, tid: 31489 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31489, switch_out: 1 }
+cpu: 2, pid: 31463, tid: 31496 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31496, switch_out: 1 }
+cpu: 3, pid: 31463, tid: 31491 { type: context_switch, next_prev_pid: 31463, next_prev_tid: 31491, switch_out: 0 }
+
+	It is possible as well to use event.misc & perf.PERF_RECORD_MISC_SWITCH_OUT
+	to figure out if this is a context switch in or out of the monitored threads.
+
+	If bored, please add command line option parsing support for these options :-)
+    """
+    # main(context_switch = 1, thread = 31463)
+    main()