Messages in this thread |  | | | Date | Tue, 5 Feb 2008 20:02:06 +0100 | | From | "Bart Van Assche" <> | | Subject | Re: Integration of SCST in the mainstream Linux kernel |
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On Feb 5, 2008 6:10 PM, Erez Zilber <erezz@voltaire.com> wrote: > One may claim that STGT should have lower performance than SCST because > its data path is from userspace. However, your results show that for > non-IB transports, they both show the same numbers. Furthermore, with IB > there shouldn't be any additional difference between the 2 targets > because data transfer from userspace is as efficient as data transfer > from kernel space. > > The only explanation that I see is that fine tuning for iSCSI & iSER is > required. As was already mentioned in this thread, with SDR you can get > ~900 MB/sec with iSER (on STGT).
My most recent measurements also show that one can get 900 MB/s with STGT + iSER on an SDR IB network, but only for very large block sizes (>= 100 MB). A quote from Linus Torvalds is relevant here (February 5, 2008):
Block transfer sizes over about 64kB are totally irrelevant for 99% of all people.
Please read my e-mail (posted earlier today) with a comparison for 4 KB - 64 KB block transfer sizes between SCST and STGT.
Bart Van Assche.
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