Ivan Voras wrote:
2009/2/13 Scott Long <[email protected]>:
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.
I don't have a magic universal testing suite in my back pocket, sorry.
You need to look at your expected workload and develop tests to simulate
it. When I do testing during driver development, I try a lot of
different parallel, sequential, large i/o, and small i/o combinations.
(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)
This is completely false. Disks can't do sequential i/o very well due
to the physical limits of long seek times, but those seek times can be
greatly amortized, even in a random workload, with tagged queueing and
parallel dispatch from the OS. Bonnie simply cannot exercise this very
well.
Bonnie tests system latency for discrete I/O's. That is all it tests.
Scott
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