On Wed, 2013-10-02 at 01:14 +0800, Xianghua Xiao wrote: > I used lio-utils to get iscsi working, however during testing I found > out that only 2 out of 12 cores are being used by LIO-TARGET(iblock), > why is that? > > Used SCST in the past and the workload was shared by all the cores by > default, so it's a surprise to me with LIO-iscsi that it picks one > core for Tx and one core for Rx, the rest cores are sitting idle? > > any help is appreciated. > Two items here. First, you'll want to bump the per TPG attribute value for default_cmdsn_depth from the default 16 to something larger (64 or 128). This value controls how many outstanding commands the initiator is allowed to dispatch on a per session basis, and increasing the value allows a larger pipe (10 Gb/sec for example) to keep more active commands in flight. The default value has also been increased to a higher value starting in v3.12-rc1 code in the patch here: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/target/iscsi?id=38f7d6edbf91693bb679bb29901c8296e7838cd9 Second, in order to scale the number of threads used for I/O submission, you'll either want to enable MC/S (multiple connections per session), or use multiple sessions (typically across multiple ports) with multipath on the client side. --nab -- To unsubscribe from this list: send the line "unsubscribe target-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
