[Stgt-devel] sg_turs on stgt iscsi drive is very slow

[FUJITA Tomonori]

From: Ming Zhang <blackmagic02881 at gmail.com>
Subject: [Stgt-devel] sg_turs on stgt iscsi drive is very slow
Date: Mon, 11 Dec 2006 11:58:27 -0500

> Pulled out the linux-2.6-target git tree, compiled stgt and iet under
> same kernel. Export a 4 disk raid0 device to ini. Ini is open-iscsi
> r598.
> 
> Want to know how efficient stgt handle context switch. 
> 
> run  sg_turs -t -n=10000 /dev/sg0 on IET drive. results is 2521/sec.

With IET, several threads handle TUR. With stgt, the single thread
handles TUR (synchronously). stgt asynchronously handles only I/O
commands (READ, WRITE, etc), which are expected to be performed
efficiently.

So I don't think the results are related with context switch at all.