]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
sched/cputime: Fix steal time accounting
authorWanpeng Li <wanpeng.li@hotmail.com>
Thu, 11 Aug 2016 05:36:35 +0000 (13:36 +0800)
committerIngo Molnar <mingo@kernel.org>
Thu, 11 Aug 2016 09:02:14 +0000 (11:02 +0200)
commitf9bcf1e0e0145323ba2cf72ecad5264ff3883eb1
treea91de94c46cb85a38fb8198ee2c65e37e4bb8347
parentc0c8c9fa210c9a042060435f17e40ba4a76d6d6f
sched/cputime: Fix steal time accounting

Commit:

  57430218317 ("sched/cputime: Count actually elapsed irq & softirq time")

... didn't take steal time into consideration with passing the noirqtime
kernel parameter.

As Paolo pointed out before:

| Why not? If idle=poll, for example, any time the guest is suspended (and
| thus cannot poll) does count as stolen time.

This patch fixes it by reducing steal time from idle time accounting when
the noirqtime parameter is true. The average idle time drops from 56.8%
to 54.75% for nohz idle kvm guest(noirqtime, idle=poll, four vCPUs running
on one pCPU).

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470893795-3527-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/sched/cputime.c