On Mon, Aug 16, 2010 at 09:14:33AM -0700, Darrick J. Wong wrote: > On Mon, Aug 09, 2010 at 05:07:23PM -0400, Christoph Hellwig wrote: > > Can you try with the new barrier implementation in the > > > > [PATCH, RFC] relaxed barriers > > > > by making cache flushes just that and not complicated drain barrier > > it should speed this case up a lot. > > Indeed it does! The barrier count increases to about 21000, but I also see > much higher throughput, about 830 transactions per second (versus 12000 and 760 > respectively before Tejun's patch). Oddly, I ran the entire suite of tests against a larger set of machines, and with Tejun's RFC patchset I didn't see nearly as much of an improvement. I have been trying to put together a new tree based on "replace barrier with sequenced flush" and Christoph's "explicitly flush/FUA" patch sets, though I've gotten lost in the weeds. :( I also experienced some sort of crash with Tejun's relaxed barrier patch on one of my systems. I was hitting the BUG_ON in drivers/scsi/scsi_lib.c, line 1115. Rather than hold on to (aging) test results any further, I'll be posting a new fsync coordination patch shortly that includes Andreas' suggestion to use the average barrier time instead of a static 500us, and a spreadsheet that shows what happens with various patches, and on a wider range of hardware. --D -- 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
