From: Rick Jones <rick.jones2@hp.com>
To: Shawn Bohrer <sbohrer@rgmadvisors.com>
Cc: netdev@vger.kernel.org
Subject: Re: Understanding lock contention in __udp4_lib_mcast_deliver
Date: Thu, 27 Jun 2013 12:58:39 -0700 [thread overview]
Message-ID: <51CC996F.3020507@hp.com> (raw)
In-Reply-To: <20130627192218.GA5936@sbohrermbp13-local.rgmadvisors.com>
On 06/27/2013 12:22 PM, Shawn Bohrer wrote:
> I'm looking for opportunities to improve the multicast receive
> performance for our application, and I thought I'd spend some time
> trying to understand what I thought might be a small/simple
> improvement. Profiling with perf I see that there is spin_lock
> contention in __udp4_lib_mcast_deliver:
>
> 0.68% swapper [kernel.kallsyms] [k] _raw_spin_lock
> |
> --- _raw_spin_lock
> |
> |--24.13%-- perf_adjust_freq_unthr_context.part.21
> |
> |--22.40%-- scheduler_tick
> |
> |--14.96%-- __udp4_lib_mcast_deliver
Are there other processes showing _raw_spin_lock time? It may be more
clear to add a --sort symbol,dso or some such to your perf report
command. Because what you show there suggests less than 1% of the
active cycles are in _raw_spin_lock.
rick jones
next prev parent reply other threads:[~2013-06-27 19:58 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-27 19:22 Understanding lock contention in __udp4_lib_mcast_deliver Shawn Bohrer
2013-06-27 19:58 ` Rick Jones [this message]
2013-06-27 20:20 ` Shawn Bohrer
2013-06-27 20:46 ` Rick Jones
2013-06-27 21:54 ` Shawn Bohrer
2013-06-27 22:03 ` Rick Jones
2013-06-27 22:44 ` Shawn Bohrer
2013-07-02 20:16 ` Eric Dumazet
2013-06-27 21:39 ` Or Gerlitz
2013-06-27 21:58 ` Shawn Bohrer
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