Re: I/O tests using elvtune to improve interactive performance

rwhron@earthlink.net
Mon, 19 Nov 2001 10:26:09 -0500


On Mon, Nov 19, 2001 at 08:09:22AM +0100, Jens Axboe wrote:
> > Test: Run growfiles tests from Linux Test Project that really hurt
> > interactive performance. Simultaneously run "ls -laR /".
> > Change the elevator read latency value with elvtune.
> > Also run mp3blaster tests.
>
> Interesting tests, thanks. I wonder if you could be convinced to do
> bonnie++ and dbench tests with the same read_latency values used? Also,
> I'm assuming you kept write latency at its default of 16384?
> --
> Jens Axboe
>

Thanks for the feedback. Write latency was 16384 for all tests.

I'm downloading dbench and bonnie++ now. I'll check them out.

I'm still not sure how to measure/quantify interactive performance.

My ideal test will have these components:

1) Simulate and measure user interactive response time.
2) Disk I/O patterns capable of making interactive performance slow.
3) Measurement of I/O throughput.
4) Note how changes with elvtune effect throughput and response time.
5) It's not too boring. (i.e. type something, use a stop watch).

It's the "measure interactive response time" that I haven't got a handle
on yet. I'm looking at the SSBA benchmarks for something that simulates
users. I don't know if it measures response time.

I could resort to a stopwatch to test interactive response, but
hopefully, something better will come to mind.

-- 
Randy Hron

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