> -----Original Message----- > From: Bart Van Assche [mailto:bart.vanassche@xxxxxxxxx] > Sent: Friday, April 03, 2009 10:09 AM > To: Vladislav Bolkhovitin > Cc: scst-devel; linux-kernel@xxxxxxxxxxxxxxx; > linux-scsi@xxxxxxxxxxxxxxx > Subject: Re: [Scst-devel] ISCSI-SCST performance (with also > IET and STGTdata) > > > On Thu, Apr 2, 2009 at 7:16 PM, Vladislav Bolkhovitin > <vst@xxxxxxxx> wrote: > > Bart Van Assche, on 04/02/2009 12:14 AM wrote: > >> I have repeated some of these performance tests for iSCSI > over IPoIB > >> (two DDR PCIe 1.0 ConnectX HCA's connected back to back). > The results > >> for the buffered I/O test with a block size of 512K (initiator) > >> against a file of 1GB residing on a tmpfs filesystem on the target > >> are as follows: > >> > >> write-test: iSCSI-SCST 243 MB/s; IET 192 MB/s. > >> read-test: iSCSI-SCST 291 MB/s; IET 223 MB/s. > >> > >> And for a block size of 4 KB: > >> > >> write-test: iSCSI-SCST 43 MB/s; IET 42 MB/s. > >> read-test: iSCSI-SCST 288 MB/s; IET 221 MB/s. > > > > Do you have any thoughts why writes are so bad? It shouldn't be so.. > > It's not impossible that with the 4 KB write test I hit the > limits of the initiator system (Intel E6750 CPU, 2.66 GHz, > two cores). Some statistics I gathered during the 4 KB write test: > Target: CPU load 0.5, 16500 mlx4-comp-0 interrupts per > second, same number of interrupts processed by each core (8250/s). > Initiator: CPU load 1.0, 32850 mlx4-comp-0 interrupts per > second, all interrupts occurred on the same core. Are you using connected mode IPoIB and setting the MTU to 4KB? Would fragmentation of IPoIB drive up the interrupt rates? > > Bart. > > -------------------------------------------------------------- > ---------------- > _______________________________________________ > Scst-devel mailing list > Scst-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/scst-devel > -- 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
