Am 15.09.2010 15:52, schrieb Anthony Liguori: > On 09/15/2010 08:30 AM, Kevin Wolf wrote: >> Am 15.09.2010 15:21, schrieb Anthony Liguori: >> >>> On 09/15/2010 07:38 AM, Kevin Wolf wrote: >>> >>>> No, we don't really care if the L2 entry is on disk. If the guest want >>>> to have its data safe it needs to issue an explicit flush anyway. The >>>> only thing we want to achieve with bdrv_write_sync is to maintain the >>>> right order between metadata updates to survive a crash without corruption. >>>> >>>> >>> Ah, yes, this is brand new :-) >>> >>> I was looking at my QED branch which is a few weeks old. >>> >> Well, the whole bdrv_pwrite_sync thing is new - with your benchmarking >> you probably caught qcow2 at its worst performance in years. > > FWIW, we queued a run reverting the sync() stuff entirely as we were > aware of that. Should have results this morning.
Okay. I think that will be helpful, even outside the context of QED. I'd be interested how much of a difference it really makes in your tests. Kevin -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
