On Fri, Mar 24, 2006 at 09:05:24AM +0100, Phil Carns wrote: > I'm not sure exactly which kernels from kernel.org are affected, but we > ran into a serious problem on the 2.6 kernel that we were using in RHEL4 > (2.6.9-22.0.1.ELsmp). The symptoms occur during a write-heavy > workloads. From the PVFS2 point of view, write throughput on one or > more servers will slow to just a few KB/s, and the AIO thread will > consume 99% of cpu time.
Ugh. Thanks for tracking this down. I guess the only thing we can do is add it to the FAQ? > David Metheny and I spent a long time tracking this down. I highly > recommend oprofile for debugging performance bugs like this. That was > what finally clued us in to where the problem was after a variety of > wrong turns :) Glad to hear oprofile paid off! ==rob -- Rob Latham Mathematics and Computer Science Division A215 0178 EA2D B059 8CDF Argonne National Labs, IL USA B29D F333 664A 4280 315B _______________________________________________ Pvfs2-developers mailing list Pvfs2-developers@beowulf-underground.org http://www.beowulf-underground.org/mailman/listinfo/pvfs2-developers
