At 02:43 PM 10/2/2006, Roland Dreier wrote: > Robert> Yes. 1250Mbytes/sec is what we expect. You say the 128 > Robert> value comes from the BIOS ? If so, we need to discuss this > Robert> with our BIOS team to find out why they limit it to 128, > Robert> perhaps it is a BIOS bug. > >Yes, I believe that the BIOS is the only place that would set that >value. We know that resetting the device makes it go back to a >different default value, and nothing in the kernel that I know of is >going to set it down to 128.
128B is the default minimum from PCIe so likely some BIOS engineer took a conservative view and chose the defaults (go figure). Setting Max Read Request Size = 4096 is preferred on any implementation as it is basically free from a chipset perspective. The chipset will likely return in cache line quantities but there is some obvious optimizations to be achieved by issuing a single DMA Read Request. Mike _______________________________________________ openib-general mailing list openib-general@openib.org http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
