Date: Sun, 30 Oct 2005 00:26:35 +0200 (CEST) From: Jan Pechanec <jp@devnull.cz> To: FreeBSD FS Mailing List <freebsd-fs@FreeBSD.ORG> Subject: initial writes with soft-updates Message-ID: <20051030000603.C11574@axxem.in.idc.cz>
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hello all, could you please shed some light on this situation? When I create many files at once with soft updates enabled, I can see some initial writes (8 in this example) during the 1st second of the operation. After that, it's silent till the next sync() - which is expected. the whole operation takes 4-5 seconds on my not brand-new 500MHz machine so I just cannot understand those first writes. I know how soft updates work and that's why I can't understand it. The system is 5.3-RELEASE-p23, 128 MB RAM with 70 MB free at least, load is nearly zero - just the test running (load averages: 0.15, 0.03, 0.01). I don't think it's about version, I have to be missing something about soft updates, just don't know what it is. When I try it with just a few files (< 10), there is no immediate write. I'm looking into soft updates chapter of McKusick's book on FreeBSD right now and cannot find an answer there either. # time for i in `jot 1000`; do touch file-$i; done real 0m4.676s user 0m0.677s sys 0m3.931s # iostat -c 100 -d ad0 14.25 8 0.11 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 please CC: on me, I'm not already a member of this list. thank you, j. -- Jan Pechanec <jp (at) devnull (dot) cz> http://www.devnull.cz
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