Hi, Running iozone with the fsync flag, or fs_mark, the performance of CFQ is far worse than that of deadline for enterprise class storage when dealing with file sizes of 8MB or less. I used the following command line as a representative test case: fs_mark -S 1 -D 10000 -N 100000 -d /mnt/test/fs_mark -s 65536 -t 1 -w 4096 -F When run using the deadline I/O scheduler, an average of the first 5 numbers will give you 448.4 files / second. CFQ will yield only 106.7. With this patch series applied (and the two patches I sent yesterday), CFQ now achieves 462.5 files / second. This patch set is still an RFC. I'd like to make it perform better when there is a competing sequential reader present. For now, I've addressed the concerns voiced about the previous posting. Review and testing would be greatly appreciated. Thanks! Jeff --- New from the last round: - removed the think time calculation I added for the sync-noidle service tree - replaced above with a suggestion from Vivek to only guard against currently active sequential readers when determining if we can preempt the sync-noidle service tree. - bug fixes Over all, I think it's simpler now thanks to the suggestions from Jens and Vivek. [PATCH 1/3] block: Implement a blk_yield function to voluntarily give up the I/O scheduler. [PATCH 2/3] jbd: yield the device queue when waiting for commits [PATCH 3/3] jbd2: yield the device queue when waiting for journal commits -- 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
