Re: Linux 2.6.29

Linus Torvalds
2009-04-03T22:10:36Z

On Fri, 3 Apr 2009, Jeff Garzik wrote:
>
> Since I am hacking on osdblk currently, I was too slack to code up a test.
> This is what bonnie++ says, at least...

Afaik, bonnie does it all in the page cache, and only tests random reads
(in the "random seek" test), not random writes.

> But I guess seeks are not very helpful on an SSD :) Any pre-built random
> write tests out there?

"fio" does well:

http://git.kernel.dk/?p=fio.git;a=summary

and I think it comes with a few example files. Here's the random write
file that Jens suggested, and that works pretty well..

It first creates a 2GB file to do the IO on, then does random 4k writes to
it with O_DIRECT.

If your SSD does badly at it, you'll just want to kill it, but it shows
you how many MB/s it's doing (or, in the sucky case, how many kB/s).

Linus

---
[global]
filename=testfile
size=2g
create_fsync=1
overwrite=1

[randwrites]
# make rw= 'randread' for random reads, 'read' for reads, etc
rw=randwrite
bs=4k
direct=1