Messages in this thread | | | Date | Fri, 18 Sep 2009 10:15:31 -0700 (PDT) | From | david@lang ... | Subject | Re: announce: fsopbench - filesystem operations benchmark |
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On Fri, 18 Sep 2009, Tobias Oetiker wrote:
> Hi, > > As explained in a mail earlier this week I am in the process of > optimizing interactive performance for a file-server under high > write load. > > To help in this venture, I have written a benchmark for measuring > the response time of filesystem operations. > > http://oss.oetiker.ch/optools/wiki/fsopbench > > The benchmark program is able to generate a artificial filesystem > tree with a file size distribution similar to a home directory tree. > > To simulate the write load it can fork of several writer processes > in the background. > > It shows similar results on all configurations I have tested. > In the example below you see: > > * lstat: 10 times slower > * reading the first byte of a file: 80 times slower > * reading a directory entry: 16 times slower > * read rate: 40 times lower
lower and slower than what?
David Lang
> On top of that the standard deviation of the measurments goes way > up with extreme maximal wait times in the 1 second range. > > Some numbers form 2.6.31 with cfq on an Areca HW Raid6 (the results > from single disks are similar but less pronounced) > > Reading Only - Mode 30s Interval > ----------------------------------------------------------------- > A read dir cnt 29512 min 0.001 ms max 14.273 ms mean 0.081 ms stdev 0.694 > B lstat file cnt 27797 min 0.006 ms max 12.471 ms mean 0.071 ms stdev 0.571 > C open file cnt 22644 min 0.013 ms max 0.390 ms mean 0.019 ms stdev 0.012 > D rd 1st byte cnt 22644 min 0.114 ms max 23.614 ms mean 0.591 ms stdev 1.464 > E read rate 71.492 MB/s > > In-Competition with 6 Writers - Mode 30s Interval > ----------------------------------------------------------------- > A read dir cnt 625 min 0.001 ms max 167.049 ms mean 1.355 ms stdev 11.462 > B lstat file cnt 589 min 0.006 ms max 182.580 ms mean 0.503 ms stdev 7.747 > C open file cnt 479 min 0.014 ms max 0.134 ms mean 0.021 ms stdev 0.011 > D rd 1st byte cnt 479 min 0.180 ms max 1114.885 ms mean 40.708 ms stdev 143.536 > E read rate 1.566 MB/s > > I have been testing some patches provided by Corrado Zoccolo but no > solution has been found yet. > > cheers > tobi > >
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