From: Cong Wang <xiyou.wangcong@gmail.com>
To: netdev@vger.kernel.org
Subject: Re: Spinlock spinning in __inet_hash_connect
Date: Wed, 6 Mar 2013 11:10:06 +0000 (UTC) [thread overview]
Message-ID: <kh786e$r70$1@ger.gmane.org> (raw)
In-Reply-To: CAKF7Hnf_EyF38OEKk2rJEvEvn+eftJ4CaHN7-SszqbZius81yg@mail.gmail.com
On Wed, 06 Mar 2013 at 09:52 GMT, Johannes Rudolph <johannes.rudolph@googlemail.com> wrote:
> Hello all,
>
> I hope I'm on the correct mailing list for raising this issue. We are
> seeing an issue while running a load test with jmeter against a web
> server [1]. The test suite uses 50 threads to connect to a localhost
> web server, runs one http request per connection and then loops. What
> happens is that after the test runs for about 10 seconds (~ 100000
> connections established / closed) the CPU load goes up and connection
> rates slow down massively (see [1] for a chart). With `perf top` I'm
> observing this on the _client_ side:
>
> 41.39% [kernel] [k] __ticket_spin_lock
> 16.83% [kernel] [k]
> __inet_check_established
> 12.50% [kernel] [k] __inet_hash_connect
> 4.35% [kernel] [k] __ticket_spin_unlock
>
It seems both IPv6 and IPv4 call paths contest for spin_lock(&head->lock),
so I am just wondering if we could use RCU to protect the iteration of
inet_bind_bucket_for_each().
next prev parent reply other threads:[~2013-03-06 11:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-06 9:52 Spinlock spinning in __inet_hash_connect Johannes Rudolph
2013-03-06 11:10 ` Cong Wang [this message]
2013-03-06 11:17 ` David Laight
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