On Thu, 28 Aug 2008 16:39:22 +0300 "Alexander Nezhinsky" <nezhinsky@xxxxxxxxx> wrote: > Sorry, I missed the list in my previous reply... > > On Thu, Aug 28, 2008 at 2:09 AM, FUJITA Tomonori > <fujita.tomonori@xxxxxxxxxxxxx> wrote: > > On Wed, 27 Aug 2008 20:22:42 +0300 > > "Alexander Nezhinsky" <nezhinsky@xxxxxxxxx> wrote: > >> On Wed, Aug 27, 2008 at 8:01 PM, FUJITA Tomonori > >> <fujita.tomonori@xxxxxxxxxxxxx> wrote: > >> > >> > Thanks. But you can do faster. This patch incurs the thread and pipe > >> > notification overheads. You don't need bs_thread stuff. See bs_aio.c > >> > >> Sure. I intended to do it that way later. I'm going to send some performance > >> results over ISER in a couple of days, so i first used this > >> straightforward implementation. > > > > Nice. > > > >> Moreover, it is also interesting to measure *with* the thread'n'pipe > >> overhead because > >> this way you only exclude I/O. It can be later compared with a version > >> without threads > >> to assess their impact. > > > > Yeah, the results should be interesting because we plan to remove the > > thread mechanism (well, we need to wait for the AIO support in Linux > > kernel). > > > >> > After that, you can do more faster. You can use sendfile (send data > >> > without memory copy) though you need some changes to the core code. > >> > >> How is sendfile() applicable to this null i/o backing store? I am not > >> sending anything > >> to I/O anyway, so there is no memory copy to spare. > > > > You send data to an initiator without doing disk I/Os. > > > > Anyway, you are an iSER guy, so you can forget sendfile stuff. > > You mean sendfile /dev/zero --> socket or socket --> /dev/null in case of > iSCSI/TCP, don't you? I'm not sure if sendfile works with /dev/zero. You can use any file because the null backing store just sends bogus data. stgt allocates a buffer and sends bogus data in the buffer for READ commands with the null backing store. stgt can do sendfile with a file instead of allocating a buffer and sending the data in it. -- To unsubscribe from this list: send the line "unsubscribe stgt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
