Re: FreeBSD 5.3b7and poor ata performance

fandino wrote:
> Kevin Oberman wrote:
>> Also, make sure that disk write-cache is enabled on both or disabled on
>> both. 
 > write-cache was enable on all tests and disks were in UDMA5 mode.
 >


I was thought about this and since I don't known the internals of
FreeBSD all I can to do is formulate a theory about the problem.

Here are my thoughts:

I don't think about a hardware problem because Linux, OpenBSD and
windows shows a normal throughput.

The mobo has a VIA-82C686B controller with ad0 and ad2 and a Promise-
PDC20265 controller with ad4, ad5, ad6 and ad7. It doesn't matter if
test are beetween VIA, promise or other combination that you choose,
so I don't think it's a problem with the promise controller, it's
independent of controllers. Test over disks as raw devices have the
same bad throughput, this makes me think that it isn't related to
filesystem, buffer-cache, softupdates, async, etc.

Now I'm out of ideas and I would be very grateful if someone could
help me. Thank you.


> In this new round of tests I add FreeBSD witch async and OpenBSD (always
> using the same hardware). FreeBSD is by far, the worst throughput of all
> (about 50% slower than others) :-?
> 
> GNU/Linux 2.4.18 with ext2:               56848 K/sec
> FreeBSD 5.3b7 with default fs:            26347 K/sec
> FreeBSD 5.3b7 with default fs(async):     26566 K/sec
> FreeBSD 5.3b7 ata raid0* (two disks):     26131 K/sec
> FreeBSD 5.3b7 geom stripe* (two disks):   30063 K/sec
> FreeBSD 5.3b7 geom stripe** (four disks): 31891 K/sec
> OpenBSD 3.5 UFS fs:                       55277 K/sec
> 
> * Each disk of the raid had a throughput of approx. 15000 K/sec
> ** Each disk of the raid had a throughput of approx. 7500 K/sec
> Each disk of the read split the throughput by half.
> 
> How is possible that FreeBSD performs as bad?
> 
> 
> http://195.55.55.164/tests/bsd.txt       (original FBSD test)
> http://195.55.55.164/tests/obsd.txt      (openbsd test)
> http://195.55.55.164/tests/gstripe-4.txt (4 disks gstripe tests with async)
> http://195.55.55.164/tests/fbsd2.txt     (FBSD test with async)
> http://195.55.55.164/tests/linux.txt     (original GNU/Linux test)
> http://195.55.55.164/tests/dmesg.txt