On Fri, 2006-09-15 at 11:20 +0530, Suparna Bhattacharya wrote: > On Thu, Sep 14, 2006 at 05:03:08PM -0700, Andrew Morton wrote: > > On Thu, 14 Sep 2006 16:36:12 -0700 > > Badari Pulavarty <pbadari@xxxxxxxxxx> wrote: > > > > > Hi Andrew, > > > > > > I have been working on tracking down ~20% performance degrade for > > > sequential read performance for ext3. > > > > oop. I'd kinda prefer that we discover things like this before the patch > > gets into mainline. > > > > > Finally narrowed it down to get_blocks() support. If I force > > > ext3_get_blocks_handle() to always return 1 block - I get better > > > IO rate. I did all the usual stuff, tracked down requests, traced > > > blocksizes, looked at readahead code, looked at mpage_readpages() > > > etc.. I still can't figure out how to explain the degrade.. > > > > > > Any suggestions on how to track it down. > > > > Learn to driver Jens's blktrace stuff, find out why the IO scheduling went > > bad. > > > > Number one suspicion: the buffer_boundary() stuff isn't working. > > I think you are right about that - perhaps something along > the lines of the following patch (untested) would help ? Yep. It works :) Thanks, Badari - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
