Hi All. We are running dbench on a machine with Dual Xeon (Hyper threading turned off), 1GB RAM and 4 Drive software RAID5. The kernel is 2.4.29-xfs 1.2. We are using LVM. However similar test done using ext2 on a disk partiotion (no md or LVM) shows The throughput is find till the number of clients are Around 16. At that point the throughput plummets about 40%. We are trying to avoid that and see how we could have a consistent throughput perhaps sacrificing some peak performance. One could argue that at the point the performance drops we are actualy beggining to see I/O requests missing page cache and going to disk. That is our current guess. We try to tune the buffer age and the interval page buffer daemon runs, but had no effect on the curve. So transactional meta data operations seems not be causing the bottle neck. Are there any VM patches that smooths out the Page Cache dirty page swapping process so that we wont see this sudden drop of through put, but could have a smoother transition. I ran a kernel profiler on the test and I dont see any dentry cache flushes or inode cache flushes. Similar test done using ext2 on a disk partiotion (no md or LVM) shows us similar performances. However for ext2 when we tweak the bdflush parameters in /proc (specifically the max age of meta data buffers) we can push the point where the data throughput falls to around 40 clients. But we are more interested in finding out ways to solve the XFS case. Any insights on this ? Thanx Ravi __________________________________ Do you Yahoo!? Yahoo! Hotjobs: Enter the "Signing Bonus" Sweepstakes http://hotjobs.sweepstakes.yahoo.com/signingbonus -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
