I agree the 32-bit byte and packet counters are useless as they get pegged in a few seconds on a busy IB networks. I thought there was an effort in IBTA to fix this.
For IB counters in a Cisco switch, we read and reset the 32-bit counters once per second and keep 64-bit counters internally. This would be possible in OF too, right? Scott Weitzenkamp SQA and Release Manager Server Virtualization Business Unit Cisco Systems > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Michael Newton > Sent: Tuesday, October 17, 2006 5:10 PM > To: Hal Rosenstock > Cc: [email protected] > Subject: Re: [openib-general] sysfs exposure of port counters useless? > > On Tue, 17 Oct 2006, Hal Rosenstock wrote: > > On Tue, 2006-10-17 at 09:55, Rimmer, Todd wrote: > > > > From: Michael Newton > > > > Sent: Tuesday, October 17, 2006 3:02 AM > > > > To: [email protected] > > > > Subject: [openib-general] sysfs exposure of port > counters useless? > > > > > > > > > > > > These are 32 bit counters. The rcv/xmit_data counters > count 32-bit > > > > blocks. Also, these counts do not wrap: they peg at all 1s. > > > > At infiniband speeds, these counts can peg out very > quickly indeed, > > > > to the point they can really only be of use if they can > be reset each > > > time > > > > there read. Now if anyone who wants to use them has to > go the CLI to > > > reset > > > > them, and theres little point in reading them without > reset, why would > > > > anyone read them via sysfs? so why have them? > > > > > > > > > > We have found that while your comment is true for the > data movement > > > counters, the error counters should not peg quickly, > hence it is valid > > its true i overstated the case just a little;) .. yes error counters > should be fine and its mainly the data counters that are problematic > (tho now im not sure i havent seen the packet counters freeze when the > data ones peg out).. > > > > to read them without resetting. However it is also > useful to have an > > > ability to reset them. Of course if there are other CLI > commands which > > > do this easily, the sysfs info is of less value. > > > > There are diag tools for this. > > thats where we started.. the point im making is that exposing the data > counters in sysfs is of little use, because if you have to go to other > tools to reset, why wouldnt you use them to read as well? > > i was looking at exposing infiniband stats via PCP > (http://oss.sgi.com/projects/pcp/). This would be useful for > folk doing IB > performance testing. Its very easy to just feed in the sysfs values.. > unfortunately they turn out to be of little value. Life would > be so much > easier if there were 64 bit counters available. Instead I > will probably > need to have an additional daemon to construct them. > > > _______________________________________________ > openib-general mailing list > [email protected] > http://openib.org/mailman/listinfo/openib-general > > To unsubscribe, please visit > http://openib.org/mailman/listinfo/openib-general > _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
