linux_dsm_epyc7002/kernel/sched
Frederic Weisbecker 25e2d8c1b9 sched/cputime: Fix ksoftirqd cputime accounting regression
irq_time_read() returns the irqtime minus the ksoftirqd time. This
is necessary because irq_time_read() is used to substract the IRQ time
from the sum_exec_runtime of a task. If we were to include the softirq
time of ksoftirqd, this task would substract its own CPU time everytime
it updates ksoftirqd->sum_exec_runtime which would therefore never
progress.

But this behaviour got broken by:

  a499a5a14d ("sched/cputime: Increment kcpustat directly on irqtime account")

... which now includes ksoftirqd softirq time in the time returned by
irq_time_read().

This has resulted in wrong ksoftirqd cputime reported to userspace
through /proc/stat and thus "top" not showing ksoftirqd when it should
after intense networking load.

ksoftirqd->stime happens to be correct but it gets scaled down by
sum_exec_runtime through task_cputime_adjusted().

To fix this, just account the strict IRQ time in a separate counter and
use it to report the IRQ time.

Reported-and-tested-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1493129448-5356-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-04-27 09:08:26 +02:00
..
autogroup.c sched/autogroup: Rename auto_group.[ch] to autogroup.[ch] 2017-02-08 09:01:11 +01:00
autogroup.h sched/headers: Prepare for new header dependencies before moving code to <linux/sched/autogroup.h> 2017-03-02 08:42:28 +01:00
clock.c sched/clock: Fix broken stable to unstable transfer 2017-03-27 10:23:48 +02:00
completion.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h> 2017-03-02 08:42:34 +01:00
core.c Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-07 14:42:34 -08:00
cpuacct.c sched/cputime: Convert kcpustat to nsecs 2017-02-01 09:13:47 +01:00
cpuacct.h sched/cpuacct: Simplify the cpuacct code 2016-03-21 11:00:28 +01:00
cpudeadline.c sched/core: Remove the tsk_cpus_allowed() wrapper 2017-03-02 08:42:24 +01:00
cpudeadline.h sched/deadline: Split cpudl_set() into cpudl_set() and cpudl_clear() 2016-09-05 13:29:43 +02:00
cpufreq_schedutil.c cpufreq: schedutil: Fix per-CPU structure initialization in sugov_start() 2017-03-21 01:03:08 +01:00
cpufreq.c cpufreq / sched: Pass flags to cpufreq_update_util() 2016-08-16 22:14:55 +02:00
cpupri.c sched/core: Remove the tsk_cpus_allowed() wrapper 2017-03-02 08:42:24 +01:00
cpupri.h sched/cpupri: Remove unnecessary definitions in cpupri.h 2014-11-16 10:58:59 +01:00
cputime.c sched/cputime: Fix ksoftirqd cputime accounting regression 2017-04-27 09:08:26 +02:00
deadline.c sched/deadline: Use deadline instead of period when calculating overflow 2017-03-16 09:37:38 +01:00
debug.c sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
fair.c Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-07 14:42:34 -08:00
features.h sched/fair: Make select_idle_cpu() more aggressive 2017-03-02 08:50:17 +01:00
idle_task.c sched/core: Add wrappers for lockdep_(un)pin_lock() 2017-01-14 11:29:30 +01:00
idle.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/idle.h> 2017-03-02 08:42:26 +01:00
loadavg.c sched/loadavg: Use {READ,WRITE}_ONCE() for sample window 2017-03-16 09:21:01 +01:00
Makefile sched/autogroup: Rename auto_group.[ch] to autogroup.[ch] 2017-02-08 09:01:11 +01:00
rt.c sched/core: Remove the tsk_nr_cpus_allowed() wrapper 2017-03-02 08:42:24 +01:00
sched.h sched/cputime: Fix ksoftirqd cputime accounting regression 2017-04-27 09:08:26 +02:00
stats.c sched: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:37 -08:00
stats.h sched/headers: Move cputime functionality from <linux/sched.h> and <linux/cputime.h> into <linux/sched/cputime.h> 2017-03-03 01:45:22 +01:00
stop_task.c sched/core: Add wrappers for lockdep_(un)pin_lock() 2017-01-14 11:29:30 +01:00
swait.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
topology.c sched/topology: Split out scheduler topology code from core.c into topology.c 2017-02-07 10:58:12 +01:00
wait.c sched/headers: fix up header file dependency on <linux/sched/signal.h> 2017-03-08 10:36:03 -08:00