From a9e3760b0838299649c0d57cca44daaf40ba3c33 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 14 Sep 2026 22:12:34 -1000 Subject: sched_ext: Maintain an online cid mask in the scheduler arena Schedulers on the default cid mapping treat [0, nr_online_cids) as the online set and restart on hotplug. Schedulers that install their own mapping with scx_bpf_cid_override() have no way to learn which cids are online: the count no longer identifies members and the CPU-form cpumask is unusable from cid programs. This is an obvious hole in the cid API. Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's arena, allocated alongside the per-CPU scratch masks and populated after the cid mapping is finalized and before ops.init(), for child schedulers too. The pointer stays valid through ops.exit() with no reference to take. It is the arena offset as a void pointer, the same form struct_ops arena arguments arrive in. The verifier types the void return as a scalar for the program's arena cast. The mask follows the SCX hotplug notifications: seeded from cpu_active_mask and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask only inside a hotplug transition. Updates walk the scheduler list under the lock that also serializes unlinking. Reads are live, not atomic snapshots. Root initialization excludes hotplug. v2: Reworded the getter kerneldoc (Andrea Righi). Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- scripts/bootgraph.pl | 224 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 224 insertions(+) create mode 100755 scripts/bootgraph.pl (limited to 'scripts/bootgraph.pl') diff --git a/scripts/bootgraph.pl b/scripts/bootgraph.pl new file mode 100755 index 000000000..79c903292 --- /dev/null +++ b/scripts/bootgraph.pl @@ -0,0 +1,224 @@ +#!/usr/bin/env perl +# SPDX-License-Identifier: GPL-2.0-only + +# Copyright 2008, Intel Corporation +# +# This file is part of the Linux kernel +# +# Authors: +# Arjan van de Ven + + +# +# This script turns a dmesg output into a SVG graphic that shows which +# functions take how much time. You can view SVG graphics with various +# programs, including Inkscape, The Gimp and Firefox. +# +# +# For this script to work, the kernel needs to be compiled with the +# CONFIG_PRINTK_TIME configuration option enabled, and with +# "initcall_debug" passed on the kernel command line. +# +# usage: +# dmesg | perl scripts/bootgraph.pl > output.svg +# + +use strict; +use Getopt::Long; +my $header = 0; + +sub help { + my $text = << "EOM"; +Usage: +1) dmesg | perl scripts/bootgraph.pl [OPTION] > output.svg +2) perl scripts/bootgraph.pl -h + +Options: + -header Insert kernel version and date +EOM + my $std=shift; + if ($std == 1) { + print STDERR $text; + } else { + print $text; + } + exit; +} + +GetOptions( + 'h|help' =>\&help, + 'header' =>\$header +); + +my %start; +my %end; +my %type; +my $done = 0; +my $maxtime = 0; +my $firsttime = 99999; +my $count = 0; +my %pids; +my %pidctr; + +my $headerstep = 20; +my $xheader = 15; +my $yheader = 25; +my $cyheader = 0; + +while (<>) { + my $line = $_; + if ($line =~ /([0-9\.]+)\] calling ([a-zA-Z0-9\_\.]+)\+/) { + my $func = $2; + if ($done == 0) { + $start{$func} = $1; + $type{$func} = 0; + if ($1 < $firsttime) { + $firsttime = $1; + } + } + if ($line =~ /\@ ([0-9]+)/) { + $pids{$func} = $1; + } + $count = $count + 1; + } + + if ($line =~ /([0-9\.]+)\] async_waiting @ ([0-9]+)/) { + my $pid = $2; + my $func; + if (!defined($pidctr{$pid})) { + $func = "wait_" . $pid . "_1"; + $pidctr{$pid} = 1; + } else { + $pidctr{$pid} = $pidctr{$pid} + 1; + $func = "wait_" . $pid . "_" . $pidctr{$pid}; + } + if ($done == 0) { + $start{$func} = $1; + $type{$func} = 1; + if ($1 < $firsttime) { + $firsttime = $1; + } + } + $pids{$func} = $pid; + $count = $count + 1; + } + + if ($line =~ /([0-9\.]+)\] initcall ([a-zA-Z0-9\_\.]+)\+.*returned/) { + if ($done == 0) { + $end{$2} = $1; + $maxtime = $1; + } + } + + if ($line =~ /([0-9\.]+)\] async_continuing @ ([0-9]+)/) { + my $pid = $2; + my $func = "wait_" . $pid . "_" . $pidctr{$pid}; + $end{$func} = $1; + $maxtime = $1; + } + if ($line =~ /Write protecting the/) { + $done = 1; + } + if ($line =~ /Freeing unused kernel memory/) { + $done = 1; + } +} + +if ($count == 0) { + print STDERR < \n"; +print "\n"; + + +if ($header) { + my $version = `uname -a`; + my $date = `date`; + print "Kernel version: $version\n"; + $cyheader = $yheader+$headerstep; + print "Date: $date\n"; +} + +my @styles; + +$styles[0] = "fill:rgb(0,0,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[1] = "fill:rgb(0,255,0);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[2] = "fill:rgb(255,0,20);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[3] = "fill:rgb(255,255,20);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[4] = "fill:rgb(255,0,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[5] = "fill:rgb(0,255,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[6] = "fill:rgb(0,128,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[7] = "fill:rgb(0,255,128);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[8] = "fill:rgb(255,0,128);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[9] = "fill:rgb(255,255,128);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[10] = "fill:rgb(255,128,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; +$styles[11] = "fill:rgb(128,255,255);fill-opacity:0.5;stroke-width:1;stroke:rgb(0,0,0)"; + +my $style_wait = "fill:rgb(128,128,128);fill-opacity:0.5;stroke-width:0;stroke:rgb(0,0,0)"; + +my $mult = 1950.0 / ($maxtime - $firsttime); +my $threshold2 = ($maxtime - $firsttime) / 120.0; +my $threshold = $threshold2/10; +my $stylecounter = 0; +my %rows; +my $rowscount = 1; +my @initcalls = sort { $start{$a} <=> $start{$b} } keys(%start); + +foreach my $key (@initcalls) { + my $duration = $end{$key} - $start{$key}; + + if ($duration >= $threshold) { + my ($s, $s2, $s3, $e, $w, $y, $y2, $style); + my $pid = $pids{$key}; + + if (!defined($rows{$pid})) { + $rows{$pid} = $rowscount; + $rowscount = $rowscount + 1; + } + $s = ($start{$key} - $firsttime) * $mult; + $s2 = $s + 6; + $s3 = $s + 1; + $e = ($end{$key} - $firsttime) * $mult; + $w = $e - $s; + + $y = $rows{$pid} * 150; + $y2 = $y + 4; + + $style = $styles[$stylecounter]; + $stylecounter = $stylecounter + 1; + if ($stylecounter > 11) { + $stylecounter = 0; + }; + + if ($type{$key} == 1) { + $y = $y + 15; + print "\n"; + } else { + print "\n"; + if ($duration >= $threshold2) { + print "$key\n"; + } else { + print "$key\n"; + } + } + } +} + + +# print the time line on top +my $time = $firsttime; +my $step = ($maxtime - $firsttime) / 15; +while ($time < $maxtime) { + my $s3 = ($time - $firsttime) * $mult; + my $tm = int($time * 100) / 100.0; + print "$tm\n"; + $time = $time + $step; +} + +print "\n"; -- cgit v1.3.1