Hi, With the recent md updates, I can now boot 2.5.47 with linux RAID 5 devices - thanks for the good work. However, (synthetic) performance has dropped considerably; I was wondering if this is expected: 2xAthlon 2000 MP, 5xSCSI RAID 5 2.4.19 (non-smp) block output: 57MBs-1, 80% CPU block input: 92MBs-1, 89%CPU 2.4.19 (smp) block output: 65MBs-1, 92% CPU block input: 77MBs-1, 90% CPU 2.5.47 (smp) block output: 49MBs-1, 99% CPU block input: 58MBs-1, 99% CPU The change from non-smp to smp makes sense (I think); SMP locking hurts read(), but the extra CPU power helps write() parity computation. However, 2.5.47 pushes up CPU usage somewhat, and drops performance substantially.. To see if this was fs-related I tried I/O on the raw md device; however again I saw a drop from 83MBs-1 (2.4.19 smp) to 67MBs-1 (2.5.47 smp). I also tried a 2-drive RAID 1 configuration and performance "improves" from 40MBs-1 (2.4.19 smp) to 41MBs-1 (2.5.47 smp) however that's probably within the margin of error. This suggests (to me) that the problem is localized to RAID 5. Finally, I tried doing a kernel compile and, while I can't read the figures I wrote down, performance was worse. merlin - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
