Re: amanda vs 2.6

From: Gene Heskett
Date: Thu Nov 27 2003 - 12:56:53 EST


On Thursday 27 November 2003 12:16, Gene Heskett wrote:
>On Thursday 27 November 2003 08:39, William Lee Irwin III wrote:
>>On Thu, Nov 27, 2003 at 05:05:50AM -0500, Gene Heskett wrote:
>>> My $0.02, but performance like that would scare a new user right
>>> back to winderz.
>>> Around here, its thanksgiving day, and we traditionally eat way
>>> too much turkey (or something like that :) And then complain
>>> about the weight we've gained of course...
>>
>>This isn't a performance problem. This is a bug. It vaguely sounds
>> like a missed wakeup or missing setting of TIF_NEED_RESCHED, but
>> could be a number of other things too.
>>
>>(The missing setting of TIF_NEED_RESCHED theory is right if it's
>>possible to clean up after it by ignoring need_resched() in the
>>scheduler and always rescheduling.)
>
>Well, running 2.6.0-test11, I just discovered I'm back to being
> unable to 'su amanda' again. It worked the first time, but I got
> rejected frorm unpacking the lastest amanda-2.4.4p1-20031126.tar.gz
> due to a lack of permissions, so I exited, chowned the archive to
> what it was supposed to be, but cannot now do another su amanda in
> order to start the install of this latest snapshot.
>
>The process just hangs, never comeing back to a prompt. I never had
>any troubles with that useing test9, so I guess its reboot time
>again.
>
>However, IMO this is a major problem, and needs fixed before 2.6.0.

Rebooted to 2.6.0-test10, deadline scheduler now, and have managed to
do an 'su amanda' at least twice without any hangs.

Three times now, no problems. 4 times, exited the last one with a
ctrl-d instead of an exit string, and now the 5th time is hung. Is
ctrl-d no longer a valid shell exit option? Finding the su PID, and
catting /proc/PID/wchan returns this just as it did yesterday:

[root@coyote root]# ps -ea |grep su
26658 pts/1 00:00:00 su
[root@coyote root]# cat /proc/26658/wchan
sys_wait4[root@coyote root]#

Comment on schedulers, deadline seems to leave me with the snappiest
machine response, with cfq a close second. The default anticipatory
just doesn't have the right 'feel' to it.

Also, setiathome only did 3 units yesterday, and it normally does 4 to
5. With the overcommit_memory non-zeroed, the machine was an
arthritic, stuttering as it barked, spastic dog.

Or, any cat could have caught that mouse...

--
Cheers, Gene
AMD K6-III@500mhz 320M
Athlon1600XP@1400mhz 512M
99.27% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com attornies please note, additions to this message
by Gene Heskett are:
Copyright 2003 by Maurice Eugene Heskett, all rights reserved.

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