From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] locking/qspinlock_stat: Count instances of nested lock slowpaths
Date: Wed, 17 Oct 2018 09:38:33 +0200 [thread overview]
Message-ID: <20181017073833.GE3121@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1539697507-28084-1-git-send-email-longman@redhat.com>
On Tue, Oct 16, 2018 at 09:45:06AM -0400, Waiman Long wrote:
> Queued spinlock supports up to 4 levels of lock slowpath nesting -
> user context, soft IRQ, hard IRQ and NMI. However, we are not sure how
> often the nesting happens. So 3 more per-cpu stat counters are added
> to track the number of instances where nesting index goes to 1, 2 and
> 3 respectively.
>
> On a dual-socket 64-core 128-thread Zen server, the following were stat
> counter values under different circumstances.
>
> State slowpath index1 index2 index3
> ----- -------- ------ ------ -------
> After bootup 1,012,150 82 0 0
> After parallel build + perf-top 125,195,009 82 0 0
Would probably be good to check a network workload.
next prev parent reply other threads:[~2018-10-17 7:38 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-16 13:45 Waiman Long
2018-10-16 13:45 ` [PATCH 2/2] locking/pvqspinlock: Extend node size when pvqspinlock is configured Waiman Long
2018-10-17 9:12 ` [tip:locking/core] " tip-bot for Waiman Long
2018-10-17 7:38 ` Peter Zijlstra [this message]
2018-10-17 21:06 ` [PATCH 1/2] locking/qspinlock_stat: Count instances of nested lock slowpaths Waiman Long
2018-10-18 9:05 ` Peter Zijlstra
2018-10-17 9:11 ` [tip:locking/core] " tip-bot for Waiman Long
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