On Thursday 18 November 2010, edA-qa mort-ora-y wrote: > I am using CALLGRIND_START_INSTRUMENTATION and STOP at some key > locations in my code. In one location it works as expected, collecting > data only for the part of the code I'm interested in. In the other > location it collects data for other threads at the same time, not just > the part I'm interested in. > > Is START/STOP thread sensitive, or is it program wide? That is, can I > actually record data only for a single thread?
Switching the instrumentation mode is a global option, ie. program wide. There is no other way, as the instrumentation is added to the code, and every thread will execute it. With instrumentation on, you still can decide not to aggregate events in given threads by switching the collection state on/off with CALLGRIND_TOGGLE_COLLECT. The collection state is thread specific. The big difference between instrumentation and collection state is the following: if instrumentation is switched off, the state of the cache is not updated. Thus, after switching instrumentation state on, callgrind starts with a freshly initialized cache, ie. you will get a lot of cold misses. This would not happen in reality, as of course, a cache is always active. Either these wrong cold misses do not matter for you, or you should switch on instrumentation before starting to collect the events, to make sure that the cache is "warmed up". Thus, with instrumentation on, and collection off, the cache state will still be updated and valid, and you just do count events (collection on) or not (collection off). This is probably the thing you want. The option to switch instrumentation mode is only useful for "fast forwarding" over uninteresting, large parts of the code, where you want all threads to progress fast. Best, Josef > > > I already know about the separate-threads option, but that is a bit > clumsier to analyze later. Plus the code I'm interested in does actually > run in multiple threads, it'd be nice to have them combined. > ------------------------------------------------------------------------------ Beautiful is writing same markup. Internet Explorer 9 supports standards for HTML5, CSS3, SVG 1.1, ECMAScript5, and DOM L2 & L3. Spend less time writing and rewriting code and more time creating great experiences on the web. Be a part of the beta today http://p.sf.net/sfu/msIE9-sfdev2dev _______________________________________________ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
