On Wed, Jun 27, 2007 at 01:48:04PM -0400, Hal Rosenstock wrote: > Another approach would be to have the PMA inform the kernel that the > counters were reset (perhaps including the values prior to the reset) so > that these could be factored into the local set of counters. There is > nothing in the spec that precludes this although it has not been > implemented this way. Then there would't be a reason for a local manager > to have to play these games. It would mean that there would need to be a > performance manager running in the subnet which may not be acceptable > for some installations; not sure.
If you are going to play those sorts of games I think it would better to just effectively disable the PMA in the mellanox firmware and do the following: - The kernel periodically fetches the performance stats and aggregates them into a 64 wrapping counter. The kernel sends PMA mads into the mellanox firmware to read and reset the counters - The new 64 bit stats are exported via sysfs/proc/whatever as wrapping counters - When a PMA packet comes in the kernel services it rather than passing it on to the chip firmware. Hopefully in future we could encourage new firmware/sillicon to support exporting non-wrapping 64 bit counters to the OS so this ugly mess wouldn't be needed. FWIW, I agree with Mark that the current locally accessible counters that are exactly the same as PMA mad values are virtually useless.. Jason _______________________________________________ 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
