On Thu, 17 Jan 2008 12:48:28 +0300 Vladislav Bolkhovitin <vst@xxxxxxxx> wrote: > FUJITA Tomonori wrote: > > On Thu, 17 Jan 2008 10:27:08 +0100 > > "Bart Van Assche" <bart.vanassche@xxxxxxxxx> 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/stgt-devel@xxxxxxxxxxxxxxxx/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 But I don't know about the details so let's wait for Pete to comment on this. Perhaps Voltaire people could comment on the tgt iSER performances. - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
