On Jan 22, 2008 12:33 PM, Vladislav Bolkhovitin <vst@vlnb.net> wrote:
>
> What are the new SRPT/iSER numbers?

You can find the new performance numbers below. These are all numbers for reading from the remote buffer cache, no actual disk reads were performed. The read tests have been performed with dd, both for a block size of 512 bytes and of 1 MB. The tests with small block size learn more about latency, while the tests with large block size learn more about the maximal possible throughput.

.............................................................................................
.                           .   STGT read     SCST read    .    STGT read      SCST read    .
.                           .  performance   performance   .   performance    performance   .
.                           .  (0.5K, MB/s)  (0.5K, MB/s)  .   (1 MB, MB/s)   (1 MB, MB/s)  .
.............................................................................................

. Ethernet (1 Gb/s network) .      77             78       .        77             89       .
. IPoIB    (8 Gb/s network) .     163            185       .       201            239       .

. iSER     (8 Gb/s network) .     250            N/A       .       360            N/A       .
. SRP      (8 Gb/s network) .     N/A            421       .       N/A            683       .
.............................................................................................

My conclusion from the above numbers: the performance difference between STGT and SCST is small for a Gigabit Ethernet network. The faster the network technology, the larger the difference between SCST and STGT.

Bart.