Guys - I'm perfectly happy with 4 32-bit counters. Given the options, that's the trade-off I would have made as well. My confusion lies in the fact that pfm_num_counters is returning 8, and pfm_cell_get_event_code was erroring out after (hard-coded) 2. Carl, two nodes doesn't work for me, because each node is independent. A blade should report the same answer as a Playstation. Intel Core 2 Duos don't report 10 counters because they have 2 cores; just 5 counters because each core is programmed independently. I think the hard-coded 2 is a simple programming bug, but I sure would like some confirmation of that. - dan
> -----Original Message----- > From: stephane eranian [mailto:[EMAIL PROTECTED] > Sent: Friday, June 06, 2008 4:54 PM > To: Carl Love > Cc: Dan Terpstra; perfmon2-devel@lists.sourceforge.net > Subject: Re: [perfmon2] perfmon2 on Cell > > Hello, > > > On Fri, Jun 6, 2008 at 9:27 PM, Carl Love <[EMAIL PROTECTED]> wrote: > > Dan: > > > > Perfmon2 does not support variable sized counters. It makes the > > assumption that counter size is a known, fixed size. The implementation > > Adding support for variable size counters is on my list of things to do > soon. > By variable it will mean that not all counters will have to have the same > size > but that will be coded in the PMU description module. This is not going to > be totally dynamic, i.e., from one application to the other. > > > for cell was fixed to four 32 bit counters per node due to the lack of > > support for a variable size. We did not choose to go with eight 16 bit > > counters per node because the feeling was the overhead of having to > > invoke the interrupt handler on a 16 bit counter would be very high. > > Typically, a user will be measuring either cycles or instructions along > > with another event. Causing an interrupt every 2^16 cycles would be > > very expensive. > > > > I would have to double code but does pfm_get_num_counters() return the > > total number of counters in a system? On a cell system there are two > > nodes. Each node has a performance counter unit with four 32 bit > > counters. > > > > Supporting both 16 and 32 bit counters gets very complicated. > > Specifically in the code for handling 64 bit virtual counters. We > > talked about providing support at some future time but felt there were > > other higher priority things to do first. Also, the perfmon2 interface > > is already complex. This is one of the reason it is has not gotten > > accepted into the kernel. We felt adding variable sized counter support > > now would only add additional complexity that would further hinder > > getting it accepted. So best to try and keep things simple for now, get > > it accepted then incrementally add the complexity later. > > > > Carl Love > > > > > > On Fri, 2008-06-06 at 15:07 -0400, Dan Terpstra wrote: > >> I'm working on implementing PAPI on Cell. > >> And I'm confused. > >> Can someone tell me why pfm_get_num_counters() returns 8 for Cell (I > think > >> this is # of 16-bit counters?) when pfm_cell_get_event_code() compares > >> against a hard-coded limit of 2 (see below)? Could this limit simply > have > >> been inappropriately inherited from another platform? > >> Also, how does one distinguish between using these counters in 16-bit > mode > >> vs. 32-bit mode? > >> - d > >> > >> static int > >> pfm_cell_get_event_code(unsigned int i, unsigned int cnt, int *code) > >> { > >> if (cnt != PFMLIB_CNT_FIRST && cnt > 2) { > >> return PFMLIB_ERR_INVAL; > >> } > >> > >> *code = cell_pe[i].pme_code; > >> > >> return PFMLIB_SUCCESS; > >> } > >> > >> > >> ----------------------------------------------------------------------- > -- > >> Check out the new SourceForge.net Marketplace. > >> It's the best place to buy or sell services for > >> just about anything Open Source. > >> http://sourceforge.net/services/buy/index.php > >> _______________________________________________ > >> perfmon2-devel mailing list > >> perfmon2-devel@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/perfmon2-devel > > > > > > ------------------------------------------------------------------------ > - > > Check out the new SourceForge.net Marketplace. > > It's the best place to buy or sell services for > > just about anything Open Source. > > http://sourceforge.net/services/buy/index.php > > _______________________________________________ > > perfmon2-devel mailing list > > perfmon2-devel@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/perfmon2-devel > > ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
