Messages in this thread | | | Date | Sun, 11 Oct 2009 10:23:09 +0200 | Subject | Re: fio rand read/write regression with 2.6.32-rc3 | From | Corrado Zoccolo <> |
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On Sat, Oct 10, 2009 at 11:52 AM, Zhang, Yanmin <yanmin_zhang@linux.intel.com> wrote: > On Sat, 2009-10-10 at 10:01 +0200, Jens Axboe wrote: >> On Sat, Oct 10 2009, Zhang, Yanmin wrote: >> > Comparing with 2.6.23-rc1's result, fio rand read write has regression >> > on my 2*4 core stoakley machine (8GB memory) with a JBOD of 12 disks. >> > >> > Every disk has 8 1-GB files. Start 8 sub-processes per disk and every >> > process random chooses a file on the disk to do 36 times of file read or >> > write on the file and then choose another file. >> > >> > >> > fio_mmap_rand_read_4k regresion is about 35%. >> >> Heh, I seem to recollect I told Linus that this would cost is 30-40% >> performance. So not totally crazy. >> >> So yes, this isn't hugely unexpected. If you send me your fio job files, >> I'll try and see what I can do about it. > See the attachment. > Hi Yanmin, the fio test you sent just performs random read, no write seems involved here. I suspect that you should be able to observe the same regression if you just run on a single disk. Can you confirm? Is your disk a SATA2 rotational disk with NCQ?
Thanks, Corrado
-- __________________________________________________________________________
dott. Corrado Zoccolo mailto:czoccolo@gmail.com PhD - Department of Computer Science - University of Pisa, Italy --------------------------------------------------------------------------
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