On Wed, Aug 13, 2014 at 10:32:31AM +0800, Li Xi wrote: > Yeah, we were using non-journaled quota. And we were doing this > benchmark to confirm that xattr based implementation has extra > overhead. We will run benchmarks on journaled-quota, and let's see > what is the performance difference between non-journaled and > journaled quotas. Can you give a lot of details about exactly how you ran the benchmark (and run future benchmarks)? Was this on a ramdisk? An SSD? A HDD? How many CPU's, how many threads were creating files, etc. And do you understand where the performance overhead was coming from? Was it CPU overhead? Locking overhead? It just doesn't make sense that storing the value in the xattr, when the xattr is stored in the on-disk inode, that it should make a huge difference; the cost of the I/O should completely dominate the cost of whether we format the bytes as an integer or storing it in the in-inode xattr. So either there is a bug in the benchmark, or a bug in our code somewhere. Either way, we should find and fix it. Regards, - Ted -- 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
