I am using the Artesyn PM/PPC750F PMC in conjunction with a Ramix 100BT quad Ethernet PMC module. When the system has *low* load, the performance of the Ethernet ports on the second module is *very* slow. (will not complete `ttcp -t 10.10.1.1 -s`) If the system is heavily loaded, in this case generating lots of SCSI disk activity, the same ports have very high performance.
Note: 1. SCSI is also a PCI peripheral 2. The Ethernet ports on the processor are fine At first I thought this was a hardware, IRQ line, problem but I see the same behavior on Ethernet ports which do not share interrupt lines. (did not see anything funny with a scope either) I have come to the conclusion that the processor is caching either the PCI I/O or memory access operations. Originally I thought the problem must have been PCI memory access. I can see from gt64260_find_bridges() the I/O space is going through ioremap(). However I do not see any such mapping for PCI memory operations. (nothing in <platform>_setup.c) However after review of mptbase.c, which works, and pcnet32.c, which is slow, it appears the problem is reverse. Linux kernel version: linux-pmppc750f-prerelease_1_1 (from linux_2_4_galileo) same results using: linuxppc_2_4_devel - 2.4.21pre5 Ideas? Suggestions? Thanks ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
