# modinfo ib_sdp filename: /lib/modules/2.6.16.21-0.8-smp/updates/kernel/drivers/infiniband /ulp/sdp/ib_sdp.ko author: Michael S. Tsirkin description: InfiniBand SDP module license: Dual BSD/GPL vermagic: 2.6.16.21-0.8-smp SMP gcc-4.1 depends: ib_core,rdma_cm srcversion: 91793E4825DEBC7A2DA9366 parm: top_mem_usage:Top system wide sdp memory usage for recv (in MB). (int) parm: rcvbuf_scale:Receive buffer size scale factor. (int) parm: send_poll_thresh:Send message size thresh hold over which to sta rt polling. (int) parm: recv_poll:How many times to poll recv. (int) parm: send_poll:How many times to poll send. (int) parm: recv_poll_miss:How many times recv poll missed. (int) parm: recv_poll_hit:How many times recv poll helped. (int) parm: send_poll_miss:How many times send poll missed. (int) parm: send_poll_hit:How many times send poll helped. (int) parm: data_debug_level:Enable data path debug tracing if > 0. (int) parm: debug_level:Enable debug tracing if > 0. (int)
Scott > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Rick Jones > Sent: Friday, April 27, 2007 12:36 PM > To: Michael S. Tsirkin > Cc: [email protected] > Subject: [ofa-general] Re: why is CPU util/service demand so > much higher withSDP than TCP? > > Michael S. Tsirkin wrote: > >>Quoting Rick Jones <[EMAIL PROTECTED]>: > >>Subject: why is CPU util/service demand so much higher with > SDP than TCP? > >> > >>So, while playing around with my new netperf SDP_RR test > I've noticed that > >>a single-byte _RR test over SDP has a much higher > transactions per second > >>(ie lower latency) than over TCP over the same HCA, but the > CPU utilization > >>is _very_ much higher and the service demand (cpu per > transaction) as well. > >>CPU util being higher makes sense with a higher transaction > rate, but not > >>the increased service demand - well at least not to my > experience thusfar. > > > > > > That's expected. > > SDP by default uses polling aggressively to trade off > service demand for latency. > > You can play with recv_poll module parameter to tune that. > > Ah, so it is doing a sit and spin waiting for traffic. I'll > see about the > recv_poll module parm - is it a binary or other? > > rick jones > > _______________________________________________ > general mailing list > [email protected] > http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general > > To unsubscribe, please visit > http://openib.org/mailman/listinfo/openib-general > _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
