Re: Fwd: Fwd: VFAT performance.

From: OGAWA Hirofumi (hirofumi@mail.parknet.co.jp)
Date: Thu Jun 05 2003 - 12:54:23 EST

Rogier Wolff <R.E.Wolff@BitWizard.nl> writes:

> The way to fix this would be to be able to assign a higher cache
> priority (*) to the blocks in the FAT, and to read more than just 4k
> per seek to the FAT.

I tried it by attached *stupid* patch.

copying 500M data

        root@devron (x)[1014]# time dd if=/dev/hda6 bs=1M count=500 > /dev/null
        500+0 records in
        500+0 records out
        524288000 bytes transferred in 44.988916 seconds (11653715 bytes/sec)
        
        real 0m45.011s
        user 0m0.008s
        sys 0m8.723s

2.5.70-bk9
        root@devron (a)[1032]# time dd if=file bs=1M count=500 > /dev/null
        500+0 records in
        500+0 records out
        524288000 bytes transferred in 75.510951 seconds (6943205 bytes/sec)
        
        real 1m15.538s
        user 0m0.015s
        sys 0m16.493s

2.5.70-bk9+patch
        root@devron (a)[1024]# time dd if=file bs=1M count=500 > /dev/null
        500+0 records in
        500+0 records out
        524288000 bytes transferred in 52.034399 seconds (10075796 bytes/sec)
        
        real 0m52.041s
        user 0m0.006s
        sys 0m17.594s

You're right. It seems that that optimization has sufficient effect to
non fragment file. Thanks. 

-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
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