Re: BUG: softraid,ext3 lockup

[Elmer <elmer@linking.ee>]

all kernels I have seen are slugish on ide-raid large raw write,

However, now I got some performance test:

dualprocessor server has hda,hdb ibm-hitatchi
	7200 rpm IC35L060AVV207-0, 1860kb cache
uniprocessor  has hda,hdc(was hdb,no diff) western digital
	7200 rpm WDC WD400BB-23DEA0 2000kb cache


Also tested with hdparm -W 1

server      | writeback              |writetrough
------------|------------------------|-----------
dual + ibm: |24 sec,40MB/s,load 1-2  |90 sec 11MB/s,2-4
uni + wdc:  |36 sec,27MB/s,load 1-2  |160 sec 6MB/s,4-7..40


with harddisc writeback the problem does not manifest itself

the problem is present when I do this directly to raw partition /dev/hda2,
(while raid is running on same discs with very slim load and swap being
off, 1GB mem and lots free)

So there are two possible causes now:

1. ServerWorks CSB5 Chipset (rev 93) or driver plus hardiscs
2. Kernel itself, gets too high io performance and everything else is
stuck. So when IO troughput gets a bit higher, the bottleneck goes away.
When some other processes want a little time, they all get very stuck and
load goes to hell.


Elmer.