Messages in this thread | | | Date | Wed, 21 Nov 2001 11:51:21 +0300 | From | Hans Reiser <> | Subject | Re: Abysmal interactive performance on 2.4.linus |
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Frank de Lange wrote:
>On Mon, Nov 12, 2001 at 03:05:56PM -0500, Jeff Garzik wrote: > >>Can you try 2.4.13ac6 (not 7/8), and 2.2.20, and post a comparison? >> > >Here's the results from some tests I did: > >2.2.20 >====== >without filesystem activity >no slowdowns observed >time ls -al /usr/|sort -k 5 -n >real 0m0.121s >user 0m0.000s >sys 0m0.090s > >with filesystem activity on ext2 >no slowdowns observed >time ls -al /opt/|sort -k 5 -n >real 0m0.079s >user 0m0.010s >sys 0m0.100s > >2.4.13-ac5 >========== >no slowdowns observed >without filesystem activity >time ls -al /usr/|sort -k 5 -n >real 0m0.142s >user 0m0.000s >sys 0m0.000s > >with filesystem activity on ext2 >no slowdowns observed >time ls -al /opt/|sort -k 5 -n >real 0m0.022s >user 0m0.020s >sys 0m0.010s > >with filesystem activity on reiserfs > - it took 31 seconds to just open this small ( < 1 kb) text file (which > resides in my home directory, on an ext2 filesystem) in vi... >time ls -al /usr/|sort -k 5 -n >real 0m6.136s >user 0m0.020s >sys 0m0.020s > > >2.4.15-pre4 >=========== >without filesystem activity >no slowdowns observed >time ls -al /usr/|sort -k 5 -n >real 0m0.081s >user 0m0.010s >sys 0m0.010s > >with filesystem activity on ext2 >no slowdowns observed >time ls -al /usr/|sort -k 5 -n >real 0m0.146s >user 0m0.000s >sys 0m0.020s > >with filesystem activity on reiserfs >system behaviour erratic, some slowdowns >time ls -al /opt|sort -k5 -n >real 0m13.232s >user 0m0.020s >sys 0m0.010s > >Seems that reiserfs is the common factor here, at least on my box. This is a 35 >GB reiserfs filesystem, app 80% used, both large and small files. > >As said in my previous message, the numbers themselves don't mean squat. It is >the large delays (the fact that user+sys <<< real) which are the problem here. > >Any other magic anyone wants me to perform? Hans, you reading this? > >Cheers//Frank > Yura, see if you can reproduce this and analyze the cause. If I understand correctly, he is saying the problem is not throughput but latency. Is that correct Frank? Once Yura reproduces it, I will speculate as to the cause.
Hans
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