Philip Mucci <[EMAIL PROTECTED]> wrote on 11/28/2008 09:38:37 AM: > > I will release support for core and uncore. But uncore will be > > restricted to system-wide sessions only. It does not make sense > > to support this for per-thread session, as there is no correlation > > possible with a PID or even a CPU. > > This is true only if you assume each process wants all of the 'off-core'
> counters. > > An approach we took on SiCortex for our 'off-core' PMU, was to partition > the 256 counters into 6 blocks of 42, each process on each core gets 42 > counters, dedicated. So there is no contention for these registers, and > they can measure system-wide-events, but maintain the idea of a first > person context, since, after all that is the workload that is being > measured. When the process on that core is not active, neither is the > perfmon context...so the counts are stopped. We can do very nice > sampling on external events, DDR transactions, pciE stuff, fabric > packets, using the same interface we do for the in-core counters, and > these happen only when the process is active in non-system-wide mode. When you have two or more processes active, and one process (at least) is sampling these off-core events on its dedicated counters, don't you still end up with the same problem of getting events from other processes mixed up with yours? I can see that it does give you a better idea about the events while your process is running, because they are disabled while your process is not running. - Corey Corey Ashford Software Engineer IBM Linux Technology Center, Linux Toolchain Beaverton, OR 503-578-3507 [EMAIL PROTECTED] ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ perfmon2-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
