Date: Sat, 19 Jan 2008 21:28:23 +0100 From: Kris Kennaway <kris@FreeBSD.org> To: Kris Kennaway <kris@FreeBSD.org>, John Baldwin <jhb@freebsd.org>, freebsd-stable@freebsd.org, Peter Jeremy <peterjeremy@optushome.com.au> Subject: Re: Swapping caused by very large (regular) file size Message-ID: <47925D67.8020003@FreeBSD.org> In-Reply-To: <20080119202117.GA44697@voi.aagh.net> 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> <20080119202117.GA44697@voi.aagh.net>
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Thomas Hurst wrote:
> * 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
Thanks, I will try to reproduce.
Kris
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