Are counters virtualized on overflow? I thought they were virtualized by accumulating at context switch. Or maybe that was just perfctr. Seems to me this would imply that *all* counters would need interrupt on overflow enabled *all* the time. - d
> -----Original Message----- > From: Carl Love [mailto:[EMAIL PROTECTED] > Sent: Thursday, June 12, 2008 4:41 PM > To: [EMAIL PROTECTED] > Cc: Dan Terpstra; perfmon2-devel@lists.sourceforge.net > Subject: Re: [perfmon2] CYCLES overflow on perfmon2 on Cell > > Yes, I was actually referring to the HW configuration being disabled by > default. I will take a look to see if we did anything in the perfmon2 > code to force it on. I don't remember the code is setup to force the > overflow bit to be set in the HW register. I will need to double check > the code as there were two of us working on the code. But from the > sounds, it probably wasn't done and we will need to fix that. > > Carl Love > > On Thu, 2008-06-12 at 22:30 +0200, stephane eranian wrote: > > Carl, > > > > I know that typically interrupt generation on overflow is turned off by > default. > > What I am saying is that you should force it in software on setting the > bits in > > the default value of the register and protecting them from the user > using > > the reserved mask. Perfmon guarantees 64-bit counters by default. > Virtualization > > is achieved via the interrupt overflow, thus it needs to be enabled by > default. > > > > > > On Thu, Jun 12, 2008 at 10:24 PM, Carl Love <[EMAIL PROTECTED]> wrote: > > > I will have to take a look and see what was done. Off the top of my > > > head, I don't remember. Interrupt generation can be enabled/disabled > > > for each counter. By default they are disabled. > > > > > > Carl Love > > > > > > On Thu, 2008-06-12 at 22:19 +0200, stephane eranian wrote: > > >> Carl, > > >> > > >> If you need to set a bit to generate interrupt on overflow, like most > > >> other processors, > > >> then I suggest you leverage the default value/reserved bitmask fields > of the PMU > > >> register description table to enforce that the bit is set no matter > > >> what. We use this > > >> approach on Itanium and X86. That will avoid problems. Of this is > > >> unless, there is > > >> a valid use for turning that bit off. Note that we do also support > > >> this on Intel X86 > > >> processors when using PEBS. > > >> > > >> > > >> On Thu, Jun 12, 2008 at 10:00 PM, Carl Love <[EMAIL PROTECTED]> wrote: > > >> > > > >> > On Thu, 2008-06-12 at 15:40 -0400, Dan Terpstra wrote: > > >> >> Hi - > > >> >> In preliminary testing of PAPI on perfmon2/Cell, it appears that > the CYCLES > > >> >> event produced by pfm_get_cycle_event() is not virtualized beyond > 32 bits. > > >> >> One of the basic PAPI tests shows this quite clearly: > > >> > > > >> > Virtual 64 bit counters on CELL do work. The virtual counters work > for > > >> > the CPC tool which works directly on the perfmon2 API. > > >> > > > >> > Please make sure that the CELL pm_status register is configured to > > >> > enable interrupts on counter overflow for the counter you are > using. > > >> > Bits 0:7 of the 32 bit register where (0 is the MSB and 31 is the > LSB) > > >> > correspond to the 8 16 bit counters. For CELL, we only support 32 > bits > > >> > which means you need to set bits 0:3 in the register for counters 0 > to > > >> > 3. > > >> > > > >> > <snip> > > >> >> Is this (not) happening in the kernel or in the libpfm layer? > > >> >> Does the same apply to other events as well? > > >> >> > > >> >> - d > > >> >> > > >> > > > >> > This will be true for all events. > > >> > > > >> > Carl Love > > >> > > > >> > > > >> > > > >> > ------------------------------------------------------------------- > ------ > > >> > 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
