On Mon, 28 Jul 2008 13:34:12 +0900 Hisashi Hifumi
> >> >
> >> > Are there significant numbers of people using block size < page size in
> >> > situations where performance is important and significantly improved by
> >> > this patch? Can you give any performance numbers to illustrate perhaps?
> >> With XFS lots of people use 4k blocksize filesystems on ia64 systems
> >> with 16k pages, so an optimization like this would be useful.
> >As Nick says, we really should have some measurement results which
> >confirm this theory. Maybe we did do some but they didn't find theor
> >way into the changelog.
> >I've put the patch on hold until this confirmation data is available.
> I've got some performance number.
> I wrote a benchmark program and got result number with this program.
> This benchmark do:
> 1, mount and open a test file.
> 2, create a 512MB file.
> 3, close a file and umount.
> 4, mount and again open a test file.
> 5, pwrite randomly 300000 times on a test file. offset is aligned by IO
> 6, measure time of preading randomly 100000 times on a test file.
> The result was:
> 330 sec
> 226 sec
> Blocksize:1024 bytes
> Memory: 1GB
> On ext3/4, a file is written through buffer/block. So random read/write mixed
> or random read after random write workloads are optimized with this patch
> pagesize != blocksize environment. This test result showed this.
OK, thanks. Those are pretty nice numbers for what is probably a
fairly common workload.