On 10/10/2013 12:08 PM, Brian L. wrote:
Hi there,
I was wondering if you guys use NOOP IO scheduler when you are running fio?
I use the CFQ IO scheduler but I do put the OS into init 1 and run fio
process one at a time so that I can get accurate readings.
I was wondering what are people practice and experience in the real world.
Thanks,
Brian L.
Some flash device drivers specifically (Fusion-io does this) use the
noop scheduler to reduce latency and variance that can be introduced
when using other schedulers. Using the no-op scheduler is a reasonable
thing to do for all drives to make apples to apples, but if a driver
specifically overrides it to something else, probably worth sticking
with their settings.
init 1 is overkill. In a previous life doing a lot of measuring of
flash - I found that simply making sure the machine was "idle" you could
get easily get repeatability within 1% for devices doing several hundred
thousand IOPS, even those with on-load architectures that were sensitive
to CPU usage.
--
To unsubscribe from this list: send the line "unsubscribe fio" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
