On 2010-08-05 16:51, Chris Mason wrote: > And then we need to setup a fio job file that hammers on all the ssds at > once. I'd have it use adio/dio and talk directly to the drives. I'd do > something like this for the fio job file, but Jens Axboe is cc'd and he > might make another suggestion on the job file. I'd do something like > this in a file named ssd.fio > > [global] > size=32g > direct=1 > iodepth=8
iodepth=8 will have no effect if you don't also set a different IO engine, otherwise you would be using read(2) to fetch the data. So add ioengine=libaio to take advantage of a higher queue depth as well. Also, I didn't see Chris mention this, but if you have a newer intel box you can use hw accellerated crc32c instead. For some reason my test box always loads crc32c and not crc32c-intel, so I need to do that manually. That helps a lot with higher transfer rates. You can check support for hw crc32c by checking for the 'sse4_2' flag in /proc/cpuinfo. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
