Excerpts from Christoph Hellwig's message of 2010-12-07 04:27:49 -0500: > On Fri, Nov 19, 2010 at 10:21:35AM -0500, Mark Lord wrote: > > >I really hate to rely on this third party hearsay (from all sides), and > > >have implement TRIM support in qemu now. I'll soon install win7 and > > >will check out the TRIM patters myself. > > > > Excellent! > > I did a Windows 7 installation under qemu today, and the result is: Great, thanks for testing this. > > - it TRIMs the whole device early during the installation > - after that I see a constant stream of small trims during the > installation. It's using lots of non-contiguous ranges in a single > TRIM command, with sizes down to 8 sectors (4k) for a single range. > - after installation there's is some background-trimming going on > even when doing no user interaction with the VM at all. > - removing files leads to an instant stream of TRIMs, again vectored > and of all sizes down to 4k. Note that the TRIMs are a lot more > instant than even with btrfs and -o discard, which delays most > TRIMs until doing a sync. Btrfs will do some small trims right when the block is freed, especially in fsync heavy workloads but this is a suboptimal thing I want to fix. The code tries to gather a whole transaction worth of trims and do them after the commit is done. -chris -- 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
