Messages in this thread | | | Subject | 2.1.114 VFS code 5x slower than 2.0.33?!? | From | Zlatko Calusic <> | Date | 06 Aug 1998 19:38:53 +0200 |
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I don't know if others noticed, but deleting files in 2.1.x kernels seems way too slow. I decided to make a benchmark today, and come to a surprising results. All test were made on the same machine, unloaded and with lots of free RAM (P166MMX, 64MB RAM, IDE disk).
First I made lots of files/directories with this (quite stupid) script:
time zsh -c 'while ((a < 10000)) do x="$RANDOM/$RANDOM" mkdir -p $x : >! $x/$RANDOM ((a = a + 1)) done'
After that I first timed 'ls -al':
{2.0.33} [/tmp/foodir]% time ls -al | wc -l 1.20user 0.96sys 0:02.19real 98%CPU (125major+513minor)pagefaults 0swaps 8618
{2.1.114} [/tmp/foodir]% time ls -al | wc -l 1.25user 6.30sys 0:07.56real 99%CPU (125major+511minor)pagefaults 0swaps 8578
Notice how 2.1.114 spends much more time in the kernel (6 times more than 2.0.33). Overall it is 3 times slower.
Then I tested deleting all those files, and results were similarly bad for 2.1.x. This time, 2.1 spent slightly less time in kernel, but overall still was almost 6 times slower:
{2.0.33} [/tmp/foodir]% time rm -rf * 1.50user 33.35sys 1:30.74real 38%CPU (81major+20minor)pagefaults 0swaps
{2.1.114} [/tmp/foodir]% time rm -rf * 1.34user 21.42sys 7:13.88real 5%CPU (84major+20minor)pagefaults 0swaps
If I'm right, this implies that 2.1.114 is very bad for proxy and/or news servers, who both operate on lots of files, creating/deleting them at fast rate.
Anybody care to shed some light on this?
Later, -- Posted by Zlatko Calusic E-mail: <Zlatko.Calusic@CARNet.hr> --------------------------------------------------------------------- Modem sex begins with a handshake.
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