Re: Time sliced CFQ io scheduler

Jens Axboe
2004-12-02T14:42:18Z

On Thu, Dec 02 2004, Giuliano Pochini wrote:
>
>
> On Thu, 2 Dec 2004, Jens Axboe wrote:
>
> > Case 4: write_files, random, bs=4k
>
> Just a thought... in this test the results don't look right. Why
> aggregate bandwidth with 8 clients is higher than with 4 and 2 clients ?
> In the cfq test with 8 clients aggregate bw is also higher than with
> a single client.

I don't know what happens with the 4 client case, but it's not that
unlikely that aggregate bandwidth will be higher for more threads doing
random writes, as request coalesching will help minimize seeks.

But I did think it was strange with the 4 client case dip was strange,
it was reproducable though (as are all the results, they have very
little variance).

--
Jens Axboe