I posted this to linuxppc list originally and hope someone here with NAPI/COALESCE/RT experience can comment on... ----------------------------- I'm trying to get 834x/TSEC gianfar.c working with 2.6.33/RT. when PREEMPT is disabled gianfar driver worked well. if PREEMPT is enabled, especially when PREEMPT_RT is enabled, network(gianfar) will be disconnected in about 2-3 minutes under iperf, if NFS is used then the whole system will hang after a while when NFS is accessed. In an older version (2.6.18-rt) where NAPI is disabled, gianfar performed well under PREEMPT_RT, in the new version of gianfar, NAPI is enforced(the code is there by default and it's hard to disable NAPI in the code now), also TX COALESCE is enabled while RX COALESCE is disabled. It seems to me NAPI is now by default for Rx and COALESCE is by default for Tx. Both NAPI/COALESCE may have negative effects for real time systems, where latency is more important than throughput. Unfortunately it's hard to disable either of them now after some experiments. Is there anyone here using gianfar with PREEMPT_RT? Do I have to port an older version gianfar to get rid of NAPI at least? Thanks, Xianghua -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
