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From: Peter Zijlstra <peterz@infradead.org>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH] lockdep: do not count lock class operations without CONFIG_DEBUG_LOCKDEP
Date: Fri, 19 May 2017 11:09:10 +0200	[thread overview]
Message-ID: <20170519090910.fubv3c3ozfckavi3@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <149517756125.33116.15222517572640587072.stgit@buzz>

On Fri, May 19, 2017 at 10:06:01AM +0300, Konstantin Khlebnikov wrote:
> Currently this counter shown in /proc/lockdep if CONFIG_DEBUG_LOCKDEP=y
> This patch disables it completely if this option is disabled.
> 
> This counter might be useful for debugging lockdep itself, but for normal
> debugging it seems useless. Lockstat provides more detailed statistics.
> 
> This atomic_inc is a hot spot inside __lock_acquire() for debug kernel.
> 
> With patch "netperf -H localhost" shows some boost: 2500 -> 2600

Nothing against these patches, but I do wonder why you're performance
optimizing debug kernels ;-)

  reply	other threads:[~2017-05-19  9:09 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-19  7:06 Konstantin Khlebnikov
2017-05-19  9:09 ` Peter Zijlstra [this message]
2017-05-19  9:28   ` Konstantin Khlebnikov

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