On Sat, 4 Apr 2009 19:22:22 -0400 Theodore Tso <tytso@xxxxxxx> wrote: > > However, the full latency fixes all the writes are synchronous, so it > must be the case that the delays are caused by the fact that queue is > getting implicitly unplugged after the synchronous write, and the > problem is no longer the mixing of WRITE and WRITE_SYNC requests as > posted in the commit log for 78f707bf. If we remove the automatic > unplug for WRITE_SYNC requests, and add an explicit unplug where it is > needed, that should fix the performance regression for this particular > sqlite test case. removing the unplug is bound to be bad; after all we're waiting on the IO. But maybe it should be "make the unplug a REALLY short time". At least for rotating storage. For non-rotating .. I'd never wait. -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- 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
