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From: Mike Galbraith <efault@gmx.de>
To: Alexey Vlasov <renton@renton.name>
Cc: linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com
Subject: Re: Attaching a process to cgroups
Date: Wed, 25 Jul 2012 15:57:47 +0200	[thread overview]
Message-ID: <1343224667.5745.67.camel@marge.simpson.net> (raw)
In-Reply-To: <20120725133637.GA9169@beaver>

On Wed, 2012-07-25 at 17:36 +0400, Alexey Vlasov wrote: 
> Hi.
> 
> Now I've got almost 5k used groups and it got even worse. Now I've got
> almost 5k used groups and it got even worse.
> 
> If only write was working slower, now everything connected with cgroups
> is hardly working.
> 
> Could it be connected with synchronize_rcu()?

I'd profile it with perf, and expect to find a large pile of cycles.

> Hanging on read():
> 
> # strace -ttT cat /proc/cgroups 
> 
> 17:30:43.825005 fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 13), ...}) = 0 <0.000005>
> 17:30:43.825048 open("/proc/cgroups", O_RDONLY) = 3 <0.000014>
> 17:30:43.825085 fstat(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 <0.000004>
> 17:30:43.825125 fadvise64(3, 0, 0, POSIX_FADV_SEQUENTIAL) = 0 <0.000005>
> 17:30:43.825161 read(3, "#subsys_name\thierarchy\tnum_cgrou"..., 32768) = 112 <7.447084>

Ew.. zillion cgroups is definitely a bad idea.

-Mike


  reply	other threads:[~2012-07-25 13:57 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-19 18:58 Alexey Vlasov
2012-06-20  3:34 ` Daisuke Nishimura
2012-06-20 11:08   ` Alexey Vlasov
2012-06-20 12:28 ` Mike Galbraith
2012-06-21  7:54   ` Alexey Vlasov
2012-06-21  8:23     ` Mike Galbraith
2012-06-21  8:26       ` Mike Galbraith
2012-06-26 18:06       ` Paul E. McKenney
2012-06-27  7:23         ` Mike Galbraith
2012-06-27 17:10           ` Paul E. McKenney
2012-06-28  2:40             ` Mike Galbraith
2012-07-23 20:41       ` Andrea Righi
2012-07-24  1:19         ` Mike Galbraith
2012-07-25 13:36   ` Alexey Vlasov
2012-07-25 13:57     ` Mike Galbraith [this message]
2012-07-26 13:02       ` Alexey Vlasov
2012-07-26 14:44         ` Mike Galbraith
2012-08-08 16:40       ` Alexey Vlasov
2012-08-08 16:51         ` Paul E. McKenney
2012-08-10  9:53           ` Alexey Vlasov

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