From: Waiman Long <longman@redhat.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 0/5] locking/lockdep: Improve lockdep performance
Date: Tue, 2 Oct 2018 09:57:29 -0400 [thread overview]
Message-ID: <25661edf-2882-7019-1ef4-d79393f239ce@redhat.com> (raw)
In-Reply-To: <20181002090652.GC116695@gmail.com>
On 10/02/2018 05:06 AM, Ingo Molnar wrote:
> * Waiman Long <longman@redhat.com> wrote:
>
>> Enabling CONFIG_LOCKDEP and other related debug options will greatly
>> reduce system performance. This patchset aims to reduce the performance
>> slowdown caused by the lockdep code.
>>
>> Patch 1 just removes an inline function that wasn't used.
>>
>> Patches 2 and 3 are minor twists to optimize the code.
>>
>> Patch 4 makes class->ops a per-cpu counter.
>>
>> Patch 5 moves the lock_release() call outside of a lock critical section.
>>
>> Parallel kernel compilation tests (make -j <#cpu>) were performed on
>> 2 different systems:
>>
>> 1) an 1-socket 22-core 44-thread Skylake system
>> 2) a 4-socket 72-core 144-thread Broadwell system
>>
>> The build times with pre-patch and post-patch debug kernels were:
>>
>> System Pre-patch Post-patch %Change
>> ------ --------- ---------- -------
>> 1-socket 8m53.9s 8m41.2s -2.4%
>> 4-socket 7m27.0s 5m31.0s -26%
>>
>> I think it is the last 2 patches that yield most of the performance
>> improvement.
> Impressive speedup!
>
> Mind including the non-lockdep numbers as well, for reference?
>
> Thanks,
>
> Ingo
OK, I will include the non lockdep number for comparison. However the
debug kernel has other debugging code enabled as well so the slowdown
won't be just for the enabling of lockdep.
-Longman
prev parent reply other threads:[~2018-10-02 13:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-28 17:53 [PATCH 0/5] locking/lockdep: Improve lockdep performance Waiman Long
2018-09-28 17:53 ` [PATCH 1/5] locking/lockdep: Remove add_chain_cache_classes() Waiman Long
2018-09-28 17:53 ` [PATCH 2/5] locking/lockdep: Eliminate redundant irqs check in __lock_acquire() Waiman Long
2018-10-02 9:06 ` Ingo Molnar
2018-09-28 17:53 ` [PATCH 3/5] locking/lockdep: Add a faster path in __lock_release() Waiman Long
2018-10-02 9:03 ` Ingo Molnar
2018-09-28 17:53 ` [PATCH 4/5] locking/lockdep: Make class->ops a percpu counter Waiman Long
2018-09-28 20:25 ` kbuild test robot
2018-09-28 20:31 ` Waiman Long
2018-09-28 20:42 ` kbuild test robot
2018-10-02 9:39 ` Peter Zijlstra
2018-10-02 9:55 ` Ingo Molnar
2018-10-02 14:10 ` Waiman Long
2018-10-02 14:28 ` Peter Zijlstra
2018-10-02 18:53 ` Ingo Molnar
2018-09-28 17:53 ` [PATCH 5/5] locking/lockdep: Call lock_release after releasing the lock Waiman Long
2018-10-02 9:08 ` Ingo Molnar
2018-10-02 9:06 ` [PATCH 0/5] locking/lockdep: Improve lockdep performance Ingo Molnar
2018-10-02 13:57 ` Waiman Long [this message]
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