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Frederic Weisbecker authored
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: a499a5a1 ("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.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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