Hi, On Friday 22 February 2008, Bart Van Assche wrote: > > > This would be useful for exp-drd too. What I do now is to compare the > > > result of VG_(get_running_tid)() with a cached value in order to > > > detect when Valgrind scheduled another thread. This test is performed > > > upon every load, every store, and every time the stack pointer is > > > modified. > > > > I thought we had such an event -- I thought Josef used it in Callgrind. > > In include/pub_tool_tooliface.h I see: > > > > track_start_client_code
Actually, I use this one. But I do not fully rely on it. Callgrind has the "nice" property that it instruments a callback at begin of every basic block. And there, I adjust to VG_(get_running_tid)(). In Callgrind, I have the additional requirement the reliable track enter/leave of signal handlers. This is not possible with the hooks provided by valgrind, e.g. in the case of a longjmp from signal handler into regular code. > > track_stop_client_code > > track_pre_thread_ll_create > > track_pre_thread_ll_create > > track_pre_thread_ll_exit > > > > Are any of these good enough? (I really thought we had a > > track_thread_switch event...) > > The above is not sufficient. I have tried in exp-drd to only update > the cached thread ID when one of the above events was generated. The > result was that for several test cases the cached thread ID was not > equal to VG_(get_running_tid()). An example of such a test case is > exp-drd/tests/sigalrm.c. Did you research the reason for this? I have this quite old comment before my "TID adjustment" (bbcc.c:536): /* This is needed because thread switches can not reliable be tracked * with callback CLG_(run_thread) only: we have otherwise no way to get * the thread ID after a signal handler returns. * This could be removed again if that bug is fixed in Valgrind. * This is in the hot path but hopefully not to costly. */ Josef ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Valgrind-developers mailing list Valgrind-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-developers
