diskio low read performance

Michel Santos michel at lucenet.com.br
Sat Jan 13 11:23:41 PST 2007

Kris Kennaway disse na ultima mensagem:
> On Sat, Jan 13, 2007 at 04:58:06PM -0200, Michel Santos wrote:
>> I have two server, the main server is a Supermicro Dualcore Dual Opteron
>> and the backup is a Athlon64 X2, both with 4GB
>> The disks are the same, only the onboard SCSI is Adaptec and the other
>> is
>> LSI. Funny is that I have no difference regarding the disk read
>> performance wether I use the Opteron machine or the other
>> dmesg Opteron
>> http://suporte.lucenet.com.br/ms/dmesg.sm
>> dmesg X2
>> http://suporte.lucenet.com.br/ms/dmesg.x2
>> kernel config
>> http://suporte.lucenet.com.br/ms/kernel62
> options        SCHED_ULE               # ULE scheduler
> From the NOTES file from where you copied this:
> # SCHED_ULE is a new scheduler that has been designed for SMP and has some
> # advantages for UP as well.  It is intended to replace the 4BSD scheduler
> # over time.  NOTE: SCHED_ULE is currently considered experimental and is
> # not recommended for production use at this time.
> When investigating problems with your system, your very first step
> should be to revert the use of code marked "experimental" and "not
> recommended for production use" ;-)

I am running both (on at a time of course :) ), now for six month or so,
ULE is giving me better overall performance, either with or w/o polling. I
mean network performance. I have net.isr.enable=1 and
this way I do get the same network performance I had on the 4.11. I mean I
have no problem here.

But also I checked the ULE/BSD against my particular problem and there is
no difference at all. I get no acceptable disk read performance when
comparing what I had with 4.11, wether with ULE or with 4BSD


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