Hi Jens, I'm running Ubuntu 12.04.2, my kernel is: Linux matt-work 3.5.0-36-generic #57~precise1-Ubuntu SMP Thu Jun 20 18:21:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux Here is the output I got from blktrace / blkparse: Total (sdb): Reads Queued: 166, 664KiB Writes Queued: 3001, 12004KiB Read Dispatches: 166, 664KiB Write Dispatches: 3001, 12004KiB Reads Requeued: 0 Writes Requeued: 0 Reads Completed: 166, 664KiB Writes Completed: 3001, 1500KiB Read Merges: 0, 0KiB Write Merges: 0, 0KiB PC Reads Queued: 0, 0KiB PC Writes Queued: 0, 0KiB PC Read Disp.: 22, 3KiB PC Write Disp.: 0, 0KiB PC Reads Req.: 0 PC Writes Req.: 0 PC Reads Compl.: 10 PC Writes Compl.: 0 IO unplugs: 166 Timer unplugs: 0 On Thu, Jul 25, 2013 at 7:36 AM, Jens Axboe <axboe@xxxxxxxxx> wrote: > On 07/24/2013 02:22 PM, Matthew Eaton wrote: >> Hi guys, >> >> I'm using this simple trim test on a raw SSD but getting very low >> performance. Bandwidth seems to be tied to the block size. Am I >> doing something wrong? > > What kernel are you on? This looks like a missing unplug issue. If you > run a blktrace for a few seconds while the test is ongoing, the output > of blkparse should reveal if you are seeing timer unplugs. > > -- > Jens Axboe > -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
