Messages in this thread | | | Date | Mon, 23 Dec 2002 13:03:49 +0100 | From | Tomas Szepe <> | Subject | Re: Read this and be ashamed ;) or: Awfull performance loss since 2.4.18 to 2.4.21-pre2 |
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> 2.4.18 > 2147483648 bytes transferred in 119.140681 seconds (18024772 bytes/sec) > > 2.4.19 > 2147483648 bytes transferred in 140.305836 seconds (15305733 bytes/sec)
Well I'm getting the numbers the other way round. <g>
Machine:
$ egrep 'model name|MHz' /proc/cpuinfo model name : AMD Athlon(tm) processor cpu MHz : 996.037 $ grep MemTotal /proc/meminfo MemTotal: 516588 kB $ egrep 'Bridge|DMA rate' /proc/ide/via South Bridge: VIA vt82c686b Highest DMA rate: UDMA100 $ cat /proc/ide/ide0/hda/model ST380021A $ su -c 'hdparm -Iv /dev/hda| grep -i dma' using_dma = 1 (on) DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5 $ grep [[:blank:]]/[[:blank:]] /etc/fstab /dev/hda3 / reiserfs defaults 1 1
Tests:
$ uname -r 2.4.18 $ time sh -c 'sync; sync; sync; dd if=/dev/zero of=hoax bs=16k count=131072; sync; sync; sync' 131072+0 records in 131072+0 records out real 1m44.708s user 0m0.140s sys 0m20.340s => 19.56MB/s
$ uname -r 2.4.20 $ time sh -c 'sync; sync; sync; dd if=/dev/zero of=hoax bs=16k count=131072; sync; sync; sync' 131072+0 records in 131072+0 records out real 1m27.980s user 0m0.120s sys 0m20.290s => 23.28MB/s
I also tried machines with disks connected to various SCSI controllers and in all cases more recent kernels gave better results than older ones (sym53c8xx: two-disk raid1 - 2.4.18: ~35MB/s, 2.4.20: ~40MB/s). I'm using reiserfs 3.6 everywhere.
-- Tomas Szepe <szepe@pinerecords.com> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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