From: Bart Van Assche <bvanassche-HInyCGIudOg@public.gmane.org>
To: Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Cc: linux-rdma <linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
Subject: Re: [PATCH, RFC] mlx4: Avoid that mlx4_cmd_wait() contributes to the system load
Date: Wed, 24 Jul 2013 20:34:19 +0200 [thread overview]
Message-ID: <51F01E2B.5000201@acm.org> (raw)
In-Reply-To: <51F0097C.4010806-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
On 07/24/13 19:06, Or Gerlitz wrote:
> On 24/07/2013 19:48, Bart Van Assche wrote:
>> I saw a load of 0.5 with several different upstream kernels (3.6..3.10
>> at least). The only IB-related process that was running on the system
>> was opensmd. This is definitely reproducible. It was only a month
>> after I had noticed this phenomenon that I started searching for the
>> root cause.
> do you see it also on systems that don't run opensm?
Yes. This happens both on systems running opensm and on systems not
running opensm. A call trace from a system on which CPU load was higher
than expected is as follows:
# echo w >/proc/sysrq-trigger; dmesg -c
SysRq : Show Blocked State
task PC stack pid father
kworker/u:7 D ffff88011fa125c0 0 181 2 0x00000000
ffff880114d63b48 0000000000000046 ffff8801158d1c40 ffff880114d63fd8
ffff880114d63fd8 ffff880114d63fd8 ffffffff81613440 ffff8801158d1c40
ffffffff817a7180 ffff880114d63b80 ffffffff817a7180 000000010000ebf9
Call Trace:
[<ffffffff813ea259>] schedule+0x29/0x70
[<ffffffff813e88aa>] schedule_timeout+0x10a/0x1e0
[<ffffffff813e98e2>] wait_for_common+0xd2/0x180
[<ffffffff813e9a63>] wait_for_completion_timeout+0x13/0x20
[<ffffffffa03bfb99>] __mlx4_cmd+0x259/0x5e0 [mlx4_core]
[<ffffffffa03d60e4>] mlx4_SENSE_PORT+0x54/0xc0 [mlx4_core]
[<ffffffffa03d620f>] mlx4_do_sense_ports+0xbf/0xd0 [mlx4_core]
[<ffffffffa03d6262>] mlx4_sense_port+0x42/0xc0 [mlx4_core]
[<ffffffff81055f9c>] process_one_work+0x16c/0x4b0
[<ffffffff8105825d>] worker_thread+0x15d/0x450
[<ffffffff8105d5b0>] kthread+0xc0/0xd0
[<ffffffff813f34dc>] ret_from_fork+0x7c/0xb0
Bart.
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prev parent reply other threads:[~2013-07-24 18:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-22 15:23 [PATCH, RFC] mlx4: Avoid that mlx4_cmd_wait() contributes to the system load Bart Van Assche
[not found] ` <51ED4E60.30203-HInyCGIudOg@public.gmane.org>
2013-07-24 15:17 ` Or Gerlitz
[not found] ` <51EFF018.7050409-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2013-07-24 16:48 ` Bart Van Assche
[not found] ` <51F0055F.7000703-HInyCGIudOg@public.gmane.org>
2013-07-24 17:06 ` Or Gerlitz
[not found] ` <51F0097C.4010806-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2013-07-24 17:13 ` Bart Van Assche
2013-07-24 18:34 ` Bart Van Assche [this message]
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