From: Mike Galbraith <efault@gmx.de>
To: Michael Witten <mfwitten@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 'autogroup' sched code KILLING responsiveness
Date: Fri, 21 Jan 2011 23:27:50 +0100 [thread overview]
Message-ID: <1295648870.23779.15.camel@marge.simson.net> (raw)
In-Reply-To: <4d39ce58.cc7e0e0a.5448.59e4@mx.google.com>
On Fri, 2011-01-21 at 10:20 -0800, Michael Witten wrote:
> Bisecting shows that this commit:
>
> 5091faa449ee0b7d73bc296a93bca9540fc51d0a
> sched: Add 'autogroup' scheduling feature: automated per session task groups
> Date: Tue Nov 30 14:18:03 2010 +0100
>
> is the reason that my computer has become unusable.
>
> With that code in place, a resource-intensive activity (such as
> compiling the Linux kernel) causes my computer to become
> unresponsive for many seconds at a time; the entire screen
> does not refresh, typed keys are dropped or are handled very
> late, etc (even in Linux's plain virtual consoles).
That's not what I'm experiencing with a UP kernel...
marge:~> time perf stat -a sh -c 'true'
Performance counter stats for 'sh -c true':
49580 cache-misses # 5.170 M/sec (scaled from 37.28%)
336112 cache-references # 35.048 M/sec (scaled from 78.81%)
185857 branch-misses # 21.019 % (scaled from 62.83%)
884249 branches # 92.204 M/sec (scaled from 21.25%)
12672552 instructions # 0.553 IPC (scaled from 58.38%)
22896301 cycles # 2387.490 M/sec (scaled from 58.38%)
410 page-faults # 0.043 M/sec
0 CPU-migrations # 0.000 M/sec
13 context-switches # 0.001 M/sec
9.590115 task-clock-msecs # 1.005 CPUs
0.009540836 seconds time elapsed
real 0m0.020s
user 0m0.000s
sys 0m0.000s
marge:~>
It took 20 ms to do the above and get it to my screen while the below
was running (among others). I've got a make -j 100 running as I write
this, and don't even notice that it's running.
Can you provide some information such as hardware description,
configuration, and perhaps measurements demonstrating the problem?
top - 22:34:38 up 33 min, 22 users, load average: 104.07, 101.73, 78.13
Tasks: 675 total, 101 running, 574 sleeping, 0 stopped, 0 zombie
Cpu(s): 95.2%us, 4.8%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND
6770 root 20 0 401m 79m 29m R 46.9 1.0 3:22.66 0 mplayer
6100 root 20 0 449m 94m 18m S 2.9 1.2 1:33.82 0 Xorg
7486 root 20 0 374m 46m 17m S 2.9 0.6 0:54.02 0 konsole
7752 root 20 0 104m 66m 8072 R 1.0 0.8 0:01.76 0 cc1
9796 root 20 0 89764 49m 8028 R 1.0 0.6 0:01.21 0 cc1
9928 root 20 0 98916 59m 8164 R 1.0 0.7 0:01.18 0 cc1
10321 root 20 0 88788 49m 8116 R 1.0 0.6 0:01.06 0 cc1
10619 root 20 0 89736 50m 8068 R 1.0 0.6 0:01.00 0 cc1
11356 root 20 0 19764 8152 2300 S 1.0 0.1 0:00.01 0 as
11597 root 20 0 97212 56m 7924 R 1.0 0.7 0:00.65 0 cc1
12203 root 20 0 79332 40m 7588 R 1.0 0.5 0:00.48 0 cc1
12209 root 20 0 80760 40m 7536 R 1.0 0.5 0:00.47 0 cc1
12247 root 20 0 85252 46m 7752 R 1.0 0.6 0:00.46 0 cc1
12510 root 20 0 82192 40m 5184 R 1.0 0.5 0:00.36 0 cc1
12612 root 20 0 81172 39m 5192 R 1.0 0.5 0:00.33 0 cc1
12615 root 20 0 81160 38m 4360 R 1.0 0.5 0:00.33 0 cc1
next prev parent reply other threads:[~2011-01-21 22:27 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-21 18:20 'autogroup' sched code KILLING responsiveness Michael Witten
2011-01-21 22:27 ` Mike Galbraith [this message]
2011-01-21 22:39 ` Michael Witten
2011-01-22 3:22 ` Mike Galbraith
2011-01-22 21:23 ` Michael Witten
2011-01-23 3:32 ` Michael Witten
2011-01-23 5:42 ` Mike Galbraith
2011-01-23 10:50 ` Christian Kujau
2011-01-23 11:19 ` Christian Kujau
2011-01-23 14:54 ` Yong Zhang
2011-01-23 15:03 ` [PATCH] sched: fix autogroup nice tune on UP Yong Zhang
2011-01-23 15:16 ` Pekka Enberg
2011-01-24 3:17 ` Yong Zhang
2011-01-24 5:40 ` [PATCH V2] " Yong Zhang
2011-01-24 5:54 ` Pekka Enberg
2011-01-24 6:11 ` Yong Zhang
2011-01-24 6:18 ` Pekka Enberg
2011-01-24 7:33 ` [PATCH V3] " Yong Zhang
2011-01-24 8:01 ` Pekka Enberg
2011-01-24 9:00 ` Mike Galbraith
2011-01-24 10:51 ` [tip:sched/urgent] sched: Fix poor interactivity on UP systems due to group scheduler nice tune bug tip-bot for Yong Zhang
2011-01-23 15:15 ` 'autogroup' sched code KILLING responsiveness Ingo Molnar
2011-01-23 15:53 ` Michael Witten
2011-01-23 18:52 ` Andreas Mohr
2011-01-23 23:57 ` Christian Kujau
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