Milind <[email protected]> writes: > Thanks for the quick reply Tom. > > I (again) went over the para that you have pointed out. Most of the > discussion in that para and the Helgrind discussion seem to revolve > around single CPU. I am not seeing any references to multicore > system with concurrent running of threads . Multiple threads, > synchronization between them, deadlocks etc all seem to be talking in > the context of a single CPU. Hope I am not misreading.
I think the discussion in that paragraph is pretty clear: valgrind will never cause a threaded program to behave incorrectly according to the POSIX spec, but you get 0 concurrency && the time slicing will be different. > I am looking for collecting memory traces for a multicore, > multithreaded (hw threads) program. I think you need to look somewhere else. Side note to the valgrind devs: does the documentation need to be updated here? The last paragraph in "Support for Threads" (linked below) says that the "use of atomic instruction sequences in shared memory between processes will not work reliably", yet the 3.5.0 release notes say that the "lock" prefix on certain instructions is now respected [1]. Due to the ambiguity between threads and processes (i.e., clone), I'm not sure if this is referring to shared address spaces in threads (in which case it probably needs updating) or atomic instructions on data in sysv/posix shmem -- i.e. shm_open'd memory. I've never heard of anyone using the latter, but then again I don't interact with many people that use even posix shared memory anyway. -tom [1] http://valgrind.org/docs/manual/dist.news.html > On Thu, Jan 7, 2010 at 6:06 AM, tom fogal <[email protected]> wrote: > > > Milind <[email protected]> writes: > > [snip] > > > I am writing an application that will run on a system that > > > has multiple CPU cores and each core having multiple hardware > > > threads. With multiple CPU cores there will be simultaneous memory > > > access requests. > > > > > > I would like to know > > > - whether Valgrind supports multicore systems ? > > > - if so, how accurately does it trace the memory accesses ? > > > - if there is anyone who has already used such multicore, multiple hw > > thread > > > environment to trace memory accesses ? > > > > > > http://www.valgrind.org/docs/manual/manual-core.html#manual-core.pthreads > > > > Cheers, > > > > -tom > > > > --00504502c7adb3382d047c89ec87 > Content-Type: text/html; charset=ISO-8859-1 > Content-Transfer-Encoding: quoted-printable > > Thanks for the quick reply Tom.<br><br>I (again) went over the para that yo= > u have pointed out. Most of the discussion in that para and the Helgrind di= > scussion seem to revolve around single CPU. I am not seeing any references = > to multicore system with concurrent running of threads . Multiple threads, = > synchronization between them, deadlocks etc all seem to be talking in the c= > ontext of a single CPU. Hope I am not misreading.<br> > <br>I am looking for collecting memory traces for a multicore, multithreade= > d (hw threads) program.<br><br>Thanks,<br>- Milind<br><br><div class=3D"gma= > il_quote">On Thu, Jan 7, 2010 at 6:06 AM, tom fogal <span dir=3D"ltr"><<= > a href=3D"mailto:[email protected]";>[email protected]</a>></span= > > wrote:<br> > <blockquote class=3D"gmail_quote" style=3D"border-left: 1px solid rgb(204, = > 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Milind <<a hre= > f=3D"mailto:[email protected]";>[email protected]</a>> writes:<br> > [snip]<br> > <div class=3D"im">> I am writing an application that will run on a syste= > m that<br> > > has multiple CPU cores and each core having multiple hardware<br> > > threads. With multiple CPU cores there will be simultaneous memory<br> > > access requests.<br> > ><br> > > I would like to know<br> > > - whether Valgrind supports multicore systems ?<br> > > - if so, how accurately does it trace the memory accesses ?<br> > > - if there is anyone who has already used such multicore, multiple hw = > thread<br> > > environment to trace memory accesses ?<br> > <br> > </div> =A0<a href=3D"http://www.valgrind.org/docs/manual/manual-core.html#m= > anual-core.pthreads" target=3D"_blank">http://www.valgrind.org/docs/manual/= > manual-core.html#manual-core.pthreads</a><br> > <br> > Cheers,<br> > <font color=3D"#888888"><br> > -tom<br> > </font></blockquote></div><br> > > --00504502c7adb3382d047c89ec87-- ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ Valgrind-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/valgrind-users
