[PATCH 1/1] perf: Add support for arch- and processor-dependent symbolic event names
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From: Corey Ashford on 8 Mar 2010 15:10 This patch adds support for arch- and processor-dependent symbolic event names to the "perf stat" tool, and could be expanded to other "perf *" commands fairly easily, I suspect. To support arch-dependent event names without adding arch-dependent code to perf, I added a callout mechanism whereby perf will look for the environment variable: PERF_ARCH_DEP_LIB, and if it exists, it will try to open the string value of that variable as a shared object. If that succeeds, it looks for the symbol "parse_arch_dep_event". If that exists, that function will be called by parse_events() before all of the other event parsing functions in parse-events.c. It is passed the same arguments as the other parse_*_event functions, namely the event string and a pointer to an event attribute structure. As the code existed, "perf stat" would print out the count results, but for raw events (which is how arch-dependent events are supported in perf_events), it would just print out a raw code. This is not acceptable, especially when a symbolic name was placed on the command line. So I changed the code to save away the event name that was passed on the command line, rather than doing a reverse translation to an event string based on the event type and config fields of the attr structure. In this way, there's no need for a reverse translation function in the arch-dependent library; only a event string->attr struct function is needed. This patch was stimulated by the availability of Stephane Eranian's libpfm4 which supports translating arch- and processor-specific symbolic event names and attributes to a perf_event_attr struct. With a very thin layer on top of libpfm4, perf can make use of it with this patch. Signed-off-by: Corey Ashford <cjashfor(a)linux.vnet.ibm.com> --- |