This really needs to be in perf_events. It's the reason why perfctr is so good; extremely low overhead 64 bit reads using rdpmc + mmap.
Phil On Aug 12, 2011, at 10:07 PM, Vince Weaver wrote: > On Fri, 12 Aug 2011, Ryan Johnson wrote: >> >> Are there plans to enable the kernel support that perf events seems to >> assume already exists? > > the libpfm4 tests are likely based on the libpfm3/perfmon2 code. Ther > perfmon2 kernel patches allowed rdpmc as far as I know. > > If you want rdpmc in a perf_event kernel you're going to have to bug the > perf_event developers on the linux-kernel list. At least one of them > wasn't against the idea, but I'm sure it's a pretty low priority for them. > > Is what you're doing timing critical enough that having a read() syscall > instead is just too much? There are issues involved with rdpmc, such as > what to do if the events you've selected are multiplexing, etc. > > Vince > > > ------------------------------------------------------------------------------ > FREE DOWNLOAD - uberSVN with Social Coding for Subversion. > Subversion made easy with a complete admin console. Easy > to use, easy to manage, easy to install, easy to extend. > Get a Free download of the new open ALM Subversion platform now. > http://p.sf.net/sfu/wandisco-dev2dev > _______________________________________________ > perfmon2-devel mailing list > perfmon2-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/perfmon2-devel ------------------------------------------------------------------------------ FREE DOWNLOAD - uberSVN with Social Coding for Subversion. Subversion made easy with a complete admin console. Easy to use, easy to manage, easy to install, easy to extend. Get a Free download of the new open ALM Subversion platform now. http://p.sf.net/sfu/wandisco-dev2dev _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
