From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Pratt Subject: Re: dbench regression in 2.6 Date: Mon, 08 Sep 2003 13:02:53 -0500 Message-ID: <3F5CC44D.7030803@austin.ibm.com> References: <3F5636F5.4060000@austin.ibm.com> <200309041138.40795.vs@namesys.com> <3F574AEE.7080402@austin.ibm.com> <200309082105.37309.vs@namesys.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <200309082105.37309.vs@namesys.com> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Vladimir Saveliev Cc: reiserfs-list@namesys.com, reiserfs-dev@namesys.com Vladimir Saveliev wrote: >Hi > >On Thursday 04 September 2003 18:23, Steven Pratt wrote: > > >>Vladimir Saveliev wrote: >> >> >> >>>Hi >>> >>>On Wednesday 03 September 2003 23:04, Hans Reiser wrote: >>> >>> >>> >>> >>>>Steven Pratt wrote: >>>> >>>> >>>> >>>> >>>> >>>>>Is anyone looking into the dbench multitheaded regression in 2.6 that I >>>>>reported here a couple of weeks ago? >>>>> >>>>> >>>>> >>>>> >>>Sorry, I was unable to find your report in mail archives. Could you, >>> >>> >please, > > >>>remind what is the problem? >>> >>>I don't see any change in the >>> >>> >>> >>>>>latest trees. >>>>> >>>>> >>>>> >>>>> >>The problem showed up in 2.6.0-test1, and every kernel since. The >>problem is that from 2.5.65 (earliest data I have) to 2.5.69 dbench on >>reiserfs with 16 clients got a throughput of ~200MB/sec. In 2.5.70 >>through 2.5.75 the score went up to ~280MB/sec, a good thing. But in >>2.6.0-test1 the throughput dropped to below 50 MB/sec. Since then it >>has risen slightly but still at only around 60MB/sec. Single client >>dbench showed similar, although much less dramatic changes. No other >>file system exhibited a change in the 2.6.0-test1 kernel so this seems >>to be unique to reiserfs >> >>http://ausgsa.ibm.com/projects/l/ltcperformance/2003benchmarks/regression/results/history-graphs/dbench.reiser.throughput.plot.16.png >> >> >>> >>> >http://ltcperf.ncsa.uiuc.edu/data/history-graphs/dbench.reiser.throughput.plot.16.png > > >>see also >> >> >> >http://ltcperf.ncsa.uiuc.edu/data/history-graphs/dbench.reiser.throughput.plot.1.png > > >>Also if you go to >> >> >> >http://ltcperf.ncsa.uiuc.edu/data/2.6.0-test1/2.5.75-vs-2.6.0-test1/index.html > > >>and select the results links related to dbench resierfs you can find >>kernel profile, sar data and lots of other system information which may >>help in isolating the problem. >> >>Steve >> >> >> > >Unfortunately, I was unable to reproduce your result. On our test machine (4 >Xeons 1gb ram) results shown by reiserfs on 2.5.75 and 2.6.0-test1 are >comparable. > >So, would be you so kind to help us to track this issue? If yes, could you , >please, describe your test in more details. > Sure. >0. what is version of dbench you used: 1.2, 1.3 or 2.0? > 2.0 >1. how many time did you run dbench 16? > 4 (for each client count, results are averaged) >2. when did you mkfs, etc, did you reboot after mkfs? > No, but the fs is mkfsed between each run. >3. how much ram does machine which was running dbench have? > 8GB >4. could you please try to rerun benchmark with SMP=off, and with 2 and 4 >cpus? >5. could you also run dbench 64 and dbench 128 for reiserfs 2.5.75 and >2.6.0-test1? > > Yes, but the machine is tied up at the moment, may take me a day or so to get more time on it. >Thanks, >vs > > > Steve