Vineeth Mekkat wrote: > Thanks Rick for the message. > > My machine is a HP server rx4640 ( > http://h18000.www1.hp.com/products/quickspecs/11847_div/11847_div.HTML) > with 4 montecito processors. I understand this is a single-bus system.
That is correct. > I run up to 8 threads (of a maximum 16) so as not to 'invoke' > hyperthreading. Then measure BUS_DATA_CYCLE_ANY to calculate bus > utilization. My intention is to see if the benchmark is saturating the > memory bus with off-chip accesses. While I am not willing to put a stake in the ground and say unequivocally "yes you are saturated" I wouldn't expect to be able to go much farther if you are at 75% utilization of that bus. I do not know how well "Linux" will "park" the second thread in each core - based on that, I would suggest running cpuconfig at EFI and explicitcly disabling HT. rick jones > > Vineeth > > On 06/28/2010 03:52 PM, Rick Jones wrote: > >> Vineeth Mekkat wrote: >> >>> Hi All, >>> >>> I am trying to measure bus utilization of some benchmarks on Itanium >>> Montecito machine. I followed the procedure in >>> http://www.ice.gelato.org/oct06/pres_pdf/gelato_ICE06oct_perfmon2_eranian_hp.pdf >>> >>> and measured the bus utilization. Now, I am not sure at what >>> percentage of value is the bus saturated? Is it 100%? >> >> >> What sort of system are you measuring? A single-bus system, or a >> "cell-based" system? >> >>> Say, if my bus utilization is 75%, can I say the bus is saturated? >>> >>> I will be grateful if someone can shed some light on this. >> >> >> I'm not sure how much light I will shed, but when it comes to memory >> busses, I've never been comfortable much past 80%. > ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
