FUJITA Tomonori wrote:
On Thu, 17 Jan 2008 12:48:28 +0300
Vladislav Bolkhovitin <[EMAIL PROTECTED]> wrote:
FUJITA Tomonori wrote:
On Thu, 17 Jan 2008 10:27:08 +0100
"Bart Van Assche" <[EMAIL PROTECTED]> wrote:
Hello,
I have performed a test to compare the performance of SCST and STGT.
Apparently the SCST target implementation performed far better than
the STGT target implementation. This makes me wonder whether this is
due to the design of SCST or whether STGT's performance can be
improved to the level of SCST ?
Test performed: read 2 GB of data in blocks of 1 MB from a target (hot
cache -- no disk reads were performed, all reads were from the cache).
Test command: time dd if=/dev/sde of=/dev/null bs=1M count=2000
STGT read SCST read
performance (MB/s) performance (MB/s)
Ethernet (1 Gb/s network) 77 89
IPoIB (8 Gb/s network) 82 229
SRP (8 Gb/s network) N/A 600
iSER (8 Gb/s network) 80 N/A
These results show that SCST uses the InfiniBand network very well
(effectivity of about 88% via SRP), but that the current STGT version
is unable to transfer data faster than 82 MB/s. Does this mean that
there is a severe bottleneck present in the current STGT
implementation ?
I don't know about the details but Pete said that he can achieve more
than 900MB/s read performance with tgt iSER target using ramdisk.
http://www.mail-archive.com/[EMAIL PROTECTED]/msg00004.html
Please don't confuse multithreaded latency insensitive workload with
single threaded, hence latency sensitive one.
Seems that he can get good performance with single threaded workload:
http://www.osc.edu/~pw/papers/wyckoff-iser-snapi07-talk.pdf
Hmm, I can't find which IB hardware did he use and it's declared Gbps
speed. He declared only "Mellanox 4X SDR, switch". What does it mean?
But I don't know about the details so let's wait for Pete to comment
on this.
I added him on CC
Perhaps Voltaire people could comment on the tgt iSER performances.
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