On Jan 22, 2013, at 4:06 PM, "Atchley, Scott" <atchleyes@xxxxxxxx> wrote: > On Jan 17, 2013, at 11:19 AM, Gandalf Corvotempesta <gandalf.corvotempesta@xxxxxxxxx> wrote: > >> 2013/1/17 Atchley, Scott <atchleyes@xxxxxxxx>: >>> 10GbE should get close to 1.2 GB/s compared to 1 GB/s for IB SDR. Latency again depends on the Ethernet driver. >> >> 10GbE faster than IB SDR? Really ? > > Define faster. Throughput or latency? > > Throughput, yes. You can easily measure 1.2 GB/s using many 10GbE NICs. > > Latency, (mostly) no. IB SDR is about 4 us while the best TCP performance I have measured over 10GbE is about 16 us (interrupt coalescing turned off, NAGLE off, etc). Some vendors (e.g. Myricom and SolarFlare) have userspace, OS-bypass socket libraries for their NICs that get this down to 3-6 us. Argh, this is native IB for SDR latency. Latency of sockets on top of IB SDR will be closer to 16-20 us. Scott-- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
