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Date: Wed, 6 Mar 2013 11:10:06 +0000 (UTC) From: Cong Wang <xiyou.wangcong@...il.com> To: netdev@...r.kernel.org Subject: Re: Spinlock spinning in __inet_hash_connect On Wed, 06 Mar 2013 at 09:52 GMT, Johannes Rudolph <johannes.rudolph@...glemail.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(). -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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