Date: Sat, 19 Jan 2008 20:21:17 +0000 From: Thomas Hurst <tom.hurst@clara.net> To: Kris Kennaway <kris@FreeBSD.org> Cc: Peter Jeremy <peterjeremy@optushome.com.au>, freebsd-stable@freebsd.org, John Baldwin <jhb@freebsd.org> Subject: Re: Swapping caused by very large (regular) file size Message-ID: <20080119202117.GA44697@voi.aagh.net> In-Reply-To: <47925058.4020406@FreeBSD.org> References: <20071203054207.GA1153@aleph.niw.com.au> <4787AAF4.1020905@FreeBSD.org> <20080112033147.GX60060@server.vk2pj.dyndns.org> <200801120005.38972.jhb@freebsd.org> <20080115020316.GA47831@voi.aagh.net> <478C7B04.9080102@FreeBSD.org> <20080116182621.GA4260@voi.aagh.net> <20080119175151.GA22860@voi.aagh.net> <47925058.4020406@FreeBSD.org>
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* Kris Kennaway (kris@FreeBSD.org) wrote:
> I don't understand your test procedure, can you elaborate?
The spikes from last night are from:
(/sbin/dump -$level -LuaC128 -f - $fs | /usr/bin/tee ${target} |
/sbin/sha1 > ${target}.sha1)
Followed by:
nice -n 19 /home/freaky/bin/par2 c -t+ -r5 -m256 ${target}
Graphs from this run clearly slow a modest amount of paging activity
while it occurs; you can see the other graphs here:
http://voi.aagh.net/backupmunin/
More simply, it can be reproduced by doing this:
-# swapoff -a # clear swap
-# swapon -a
-# top |grep -A1 Mem
Mem: 1371M Active, 5727M Inact, 416M Wired, 271M Cache, 214M Buf, 124M
Free
Swap: 10G Total, 10G Free
-# ls -l voi_20080119_#usr.dmp.0
-rw-r--r-- 1 root wheel 106527672320 Jan 19 05:27
voi_20080119_#usr.dmp.0
-# cat voi_20080119_#usr.dmp.0 >/dev/null &
-% sleep 20 && top |grep -A1 Mem
Mem: 1407M Active, 5789M Inact, 431M Wired, 272M Cache, 214M Buf, 8580K
Free
Swap: 10G Total, 400K Used, 10G Free
The system's occasionally deciding to swap pages out rather than recycle
something from the huge pool of inactive/cache memory (which atm will be
mostly cached pages from this file, since this is my second test run;
the first took longer to ramp up).
-% uname -a
FreeBSD voi.nightsdawn.sf 7.0-RC1 FreeBSD 7.0-RC1 #0: Wed Jan 16
14:56:50 GMT 2008
--
Thomas 'Freaky' Hurst
http://hur.st/
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