HEADS UP: Major CAM performance regression

[Ivan Voras]

2009/2/13 Scott Long <scottl at samsco.org>:
> Ivan Voras wrote:
>>
>> Scott Long wrote:
>>
>>> I have committed a fix for this problem for FreeBSD 8-CURRENT as of SVN
>>> revision 188570. FreeBSD 7-STABLE will be updated with the fix in a few
>>> days once I've gotten confirmation that the fix works and doesn't cause
>>> any adverse side-effects.  Anyone wanting to help in this validation
>>> effort should apply the attached patch to their kernel source tree and
>>> recompile.  Please contact me directly by email to report if the problem
>>> is fixed for you.
>>
>> I notice that write performance on an ESXi 3.5 hosted system is doubled,
>> but read performance remains the same (in bonnie++).
>> On a CISS system there is no significant change.
>
> bonnie is an unreliable tool for measuring performance.

I'll try your suggestion if you have one.

(except if it's about bonnie++ primarily measuring sequential
read/write - if a system can't do sequential IO well, it probably
won't do random IO well)