Le 17 août 2014 11:21, "Howard Chu" <h...@symas.com> a écrit : > > Philippe Waroquiers wrote: > > On Sun, 2014-08-17 at 02:47 -0700, Van Snyder wrote: > >> On Sun, 2014-08-17 at 09:48 +0200, Julian Seward wrote: > >>> On 08/16/2014 03:19 AM, Van Snyder wrote: > >>>> It seems that cachegrind could be extended to do complete precise > >>>> profiling. > >>> > >>> What do you mean by "complete precise profiling"? Can you clarify? > >> > >> Trace execution of every instruction and account for its execution time, > >> including the analyses that cachegrind does to model caches. > >> > >> Produce two reports, one sorted in decreasing order of the time spent on > >> each line of source, and another sorted in decreasing order of the time > >> spent in each basic block, at last basic blocks as they are discovered > >> by tracing execution. > >> > >> I used such a tool to productive advantage thirty years ago. It didn't > >> matter that the cost was eighty times the cost of running the program on > >> its own. > >> > >> Maybe cachegrind already does this, but the description isn't clear. > > See cachegrind user manual, indicating e.g. > > "... I cache reads (Ir, which equals the number of instructions ..." > > http://www.valgrind.org/docs/manual/cg-manual.html#cg-manual.overview > > For callgrind, see e.g. the description of --cache-sim=<yes|no> > > > > What is not clear is how to compute exact execution time from the > > various stats (Ir, I1mr, Ilmr, Dr, D1mr, ...). > > (or maybe rather than exact execution time, correct relative execution > > time of each program piece). > > You would need a cycle-accurate machine model, which valgrind is not.
You may be interested into marss86 x86 cycle accurate simulator. Cheers, Francis > > -- > -- Howard Chu > CTO, Symas Corp. http://www.symas.com > Director, Highland Sun http://highlandsun.com/hyc/ > Chief Architect, OpenLDAP http://www.openldap.org/project/ > > ------------------------------------------------------------------------------ > _______________________________________________ > Valgrind-users mailing list > Valgrind-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/valgrind-users
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