On Sat, 4 Apr 2009, Jens Axboe wrote: > > Big nack on this patch. Ted, this is EXACTLY where I told you we saw big > write regressions (sqlite performance drops by a factor of 4-5). Do a > git log on fs/buffer.c and see the original patch (which does what your > patch does) and the later revert. No idea why you are now suggestion > making that exact change?! Jens, if I can re-create the 'fsync' times (I haven't yet), then the default scheduler _will_ be switched to AS. > Low latency is nice, but not at the cost of 4-5x throughput for real > world cases. I'm sorry, but that fsync thing _is_ a real-world case, and it's the one that a hell of a lot more people care about than some idiotic sqlite throughput issue. You have a test-case now. Consider it a priority, or consider CFQ to be a "for crazy servers that only care about throughput". Quite frankly, the fact that I can see _seconds_ of latencies with a really good SSD is not acceptable. The fact that it is by design is even less so. Latency is more important than throughput. It's that simple. Linus -- 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
