On Mon, 19 August 2013 12:36:43 -0700, Nicholas A. Bellinger wrote: > On Sun, 2013-08-18 at 22:43 -0600, Scott Hallowell wrote: > > I recommend pursuing a few different things.. > > First, you'll want to bump the default_cmdsn_depth from 16 to 64. > > The second is to try with write cache (buffered writes) enabled. Total agreement on these two. Depending on the storage and initiator even 64 might not be enough, so you can set default_cmdsn_depth even higher, if it makes a difference. Quite likely your results will still fall short of the samba comparison. I suspect some reasonably low-hanging optimizations in the iscsi target stack, but don't have time to get on my ladder and start picking. My favorite starting point is "perf record -ag". Take a look at the top cpu consumers, especially locking functions. Investigate anything that doesn't make sense. Another unlikely but possible problem is packet loss. iscss seems to handle bad networks less well than plain tcp. Jörn -- If every man who wrote a story which was indirectly inspired by Poe were to pay a tithe toward a monument it would be such as would dwarf the pyramids. -- Sir Arthur Conan Doyle -- 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
