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From: Nicholas N. <nj...@cs...> - 2008-09-24 21:57:12
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On Tue, 23 Sep 2008, Danny Robson wrote: > This is some interesting timing! In the last few months I've been > hacking away at Valgrind based code, looking at building performance > analysis tools. > > As part of this we have a modified Valgrind/VEX which allows threads to > run in parallel. This is mainly Valgrind core, as: > * Some of the tools are a little difficult to parallelise (as has been > pointed out in the Valgrind documentation) > * We are developing our own tools > > The main areas we looked at were code caching mechanisms and atomic > instruction implementations. We got a reasonable speedup until around 8 > CPUs. > > If people are interested in more details I can give more specifics or > can be contacted off list. I can forward code or more implementation > details. As it stands, the modifications work right now, but there is > still a reasonable amount of experiment code present. > > If this sounds like an appealing addition to Valgrind proper then I can > clean up the code into a more sane series of patches. I'm interested in hearing about it. Section 3.14 of http://valgrind.org/docs/valgrind2007.pdf discusses the difficulties of multithreading when tools use shadow memory. Do you have a solution for that, or do you just not worry about it because your tools don't use shadow memory? Nick |