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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
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Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
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+perf-diff(1)
+============
+
+NAME
+----
+perf-diff - Read perf.data files and display the differential profile
+
+SYNOPSIS
+--------
+[verse]
+'perf diff' [baseline file] [data file1] [[data file2] ... ]
+
+DESCRIPTION
+-----------
+This command displays the performance difference amongst two or more perf.data
+files captured via perf record.
+
+If no parameters are passed it will assume perf.data.old and perf.data.
+
+The differential profile is displayed only for events matching both
+specified perf.data files.
+
+If no parameters are passed the samples will be sorted by dso and symbol.
+As the perf.data files could come from different binaries, the symbols addresses
+could vary. So perf diff is based on the comparison of the files and
+symbols name.
+
+OPTIONS
+-------
+-D::
+--dump-raw-trace::
+ Dump raw trace in ASCII.
+
+--kallsyms=<file>::
+ kallsyms pathname
+
+-m::
+--modules::
+ Load module symbols. WARNING: use only with -k and LIVE kernel
+
+-d::
+--dsos=::
+ Only consider symbols in these dsos. CSV that understands
+ file://filename entries. This option will affect the percentage
+ of the Baseline/Delta column. See --percentage for more info.
+
+-C::
+--comms=::
+ Only consider symbols in these comms. CSV that understands
+ file://filename entries. This option will affect the percentage
+ of the Baseline/Delta column. See --percentage for more info.
+
+-S::
+--symbols=::
+ Only consider these symbols. CSV that understands
+ file://filename entries. This option will affect the percentage
+ of the Baseline/Delta column. See --percentage for more info.
+
+-s::
+--sort=::
+ Sort by key(s): pid, comm, dso, symbol, cpu, parent, srcline.
+ Please see description of --sort in the perf-report man page.
+
+-t::
+--field-separator=::
+
+ Use a special separator character and don't pad with spaces, replacing
+ all occurrences of this separator in symbol names (and other output)
+ with a '.' character, that thus it's the only non valid separator.
+
+-v::
+--verbose::
+ Be verbose, for instance, show the raw counts in addition to the
+ diff.
+
+-q::
+--quiet::
+ Do not show any warnings or messages. (Suppress -v)
+
+-f::
+--force::
+ Don't do ownership validation.
+
+--symfs=<directory[,layout]>::
+ Look for files with symbols relative to this directory. The optional
+ layout can be 'hierarchy' (default, matches full path) or 'flat'
+ (only matches base name). This is useful when debug files are stored
+ in a flat directory structure.
+
+-b::
+--baseline-only::
+ Show only items with match in baseline.
+
+-c::
+--compute::
+ Differential computation selection - delta, ratio, wdiff, cycles,
+ delta-abs (default is delta-abs). Default can be changed using
+ diff.compute config option. See COMPARISON METHODS section for
+ more info.
+
+--cycles-hist::
+ Report a histogram and the standard deviation for cycles data.
+ It can help us to judge if the reported cycles data is noisy or
+ not. This option should be used with '-c cycles'.
+
+-p::
+--period::
+ Show period values for both compared hist entries.
+
+-F::
+--formula::
+ Show formula for given computation.
+
+-o::
+--order::
+ Specify compute sorting column number. 0 means sorting by baseline
+ overhead and 1 (default) means sorting by computed value of column 1
+ (data from the first file other base baseline). Values more than 1
+ can be used only if enough data files are provided.
+ The default value can be set using the diff.order config option.
+
+--percentage::
+ Determine how to display the overhead percentage of filtered entries.
+ Filters can be applied by --comms, --dsos and/or --symbols options.
+
+ "relative" means it's relative to filtered entries only so that the
+ sum of shown entries will be always 100%. "absolute" means it retains
+ the original value before and after the filter is applied.
+
+--time::
+ Analyze samples within given time window. It supports time
+ percent with multiple time ranges. Time string is 'a%/n,b%/m,...'
+ or 'a%-b%,c%-%d,...'.
+
+ For example:
+
+ Select the second 10% time slice to diff:
+
+ perf diff --time 10%/2
+
+ Select from 0% to 10% time slice to diff:
+
+ perf diff --time 0%-10%
+
+ Select the first and the second 10% time slices to diff:
+
+ perf diff --time 10%/1,10%/2
+
+ Select from 0% to 10% and 30% to 40% slices to diff:
+
+ perf diff --time 0%-10%,30%-40%
+
+ It also supports analyzing samples within a given time window
+ <start>,<stop>. Times have the format seconds.nanoseconds. If 'start'
+ is not given (i.e. time string is ',x.y') then analysis starts at
+ the beginning of the file. If stop time is not given (i.e. time
+ string is 'x.y,') then analysis goes to the end of the file.
+ Multiple ranges can be separated by spaces, which requires the argument
+ to be quoted e.g. --time "1234.567,1234.789 1235,"
+ Time string is'a1.b1,c1.d1:a2.b2,c2.d2'. Use ':' to separate timestamps
+ for different perf.data files.
+
+ For example, we get the timestamp information from 'perf script'.
+
+ perf script -i perf.data.old
+ mgen 13940 [000] 3946.361400: ...
+
+ perf script -i perf.data
+ mgen 13940 [000] 3971.150589 ...
+
+ perf diff --time 3946.361400,:3971.150589,
+
+ It analyzes the perf.data.old from the timestamp 3946.361400 to
+ the end of perf.data.old and analyzes the perf.data from the
+ timestamp 3971.150589 to the end of perf.data.
+
+--cpu:: Only diff samples for the list of CPUs provided. Multiple CPUs can
+ be provided as a comma-separated list with no space: 0,1. Ranges of
+ CPUs are specified with -: 0-2. Default is to report samples on all
+ CPUs.
+
+--pid=::
+ Only diff samples for given process ID (comma separated list).
+
+--tid=::
+ Only diff samples for given thread ID (comma separated list).
+
+--stream::
+ Enable hot streams comparison. Stream can be a callchain which is
+ aggregated by the branch records from samples.
+
+COMPARISON
+----------
+The comparison is governed by the baseline file. The baseline perf.data
+file is iterated for samples. All other perf.data files specified on
+the command line are searched for the baseline sample pair. If the pair
+is found, specified computation is made and result is displayed.
+
+All samples from non-baseline perf.data files, that do not match any
+baseline entry, are displayed with empty space within baseline column
+and possible computation results (delta) in their related column.
+
+Example files samples:
+- file A with samples f1, f2, f3, f4, f6
+- file B with samples f2, f4, f5
+- file C with samples f1, f2, f5
+
+Example output:
+ x - computation takes place for pair
+ b - baseline sample percentage
+
+- perf diff A B C
+
+ baseline/A compute/B compute/C samples
+ ---------------------------------------
+ b x f1
+ b x x f2
+ b f3
+ b x f4
+ b f6
+ x x f5
+
+- perf diff B A C
+
+ baseline/B compute/A compute/C samples
+ ---------------------------------------
+ b x x f2
+ b x f4
+ b x f5
+ x x f1
+ x f3
+ x f6
+
+- perf diff C B A
+
+ baseline/C compute/B compute/A samples
+ ---------------------------------------
+ b x f1
+ b x x f2
+ b x f5
+ x f3
+ x x f4
+ x f6
+
+COMPARISON METHODS
+------------------
+delta
+~~~~~
+If specified the 'Delta' column is displayed with value 'd' computed as:
+
+ d = A->period_percent - B->period_percent
+
+with:
+ - A/B being matching hist entry from data/baseline file specified
+ (or perf.data/perf.data.old) respectively.
+
+ - period_percent being the % of the hist entry period value within
+ single data file
+
+ - with filtering by -C, -d and/or -S, period_percent might be changed
+ relative to how entries are filtered. Use --percentage=absolute to
+ prevent such fluctuation.
+
+delta-abs
+~~~~~~~~~
+Same as 'delta` method, but sort the result with the absolute values.
+
+ratio
+~~~~~
+If specified the 'Ratio' column is displayed with value 'r' computed as:
+
+ r = A->period / B->period
+
+with:
+ - A/B being matching hist entry from data/baseline file specified
+ (or perf.data/perf.data.old) respectively.
+
+ - period being the hist entry period value
+
+wdiff:WEIGHT-B,WEIGHT-A
+~~~~~~~~~~~~~~~~~~~~~~~
+If specified the 'Weighted diff' column is displayed with value 'd' computed as:
+
+ d = B->period * WEIGHT-A - A->period * WEIGHT-B
+
+ - A/B being matching hist entry from data/baseline file specified
+ (or perf.data/perf.data.old) respectively.
+
+ - period being the hist entry period value
+
+ - WEIGHT-A/WEIGHT-B being user supplied weights in the '-c' option
+ behind ':' separator like '-c wdiff:1,2'.
+ - WEIGHT-A being the weight of the data file
+ - WEIGHT-B being the weight of the baseline data file
+
+cycles
+~~~~~~
+If specified the '[Program Block Range] Cycles Diff' column is displayed.
+It displays the cycles difference of same program basic block amongst
+two perf.data. The program basic block is the code between two branches.
+
+'[Program Block Range]' indicates the range of a program basic block.
+Source line is reported if it can be found otherwise uses symbol+offset
+instead.
+
+SEE ALSO
+--------
+linkperf:perf-record[1], linkperf:perf-report[1]