Currently, Valgrind builds are produced (and tested) in Linux 32-bit and Linux 64-bit machines. Ideally, "V" builds should be produced (and tested) in Mac environments as well. Valgrind supports Snow Leopard 10.6.x now and should probably support Lion 10.7.x in the future.
Note that testing on Mac Valgrind builds have an implication - because .dSYM folders are produced, -j1 is recommended (preventing parallel processes), and this will take a long time to execute even jstests. See bug 801911 comment 8, it takes 8.5 hours on -j1 on Mac Valgrind build running jstests without --track-origins=yes.
That sounds fixable. Change Valgrind to handle races better, or run the shell under Valgrind once with a minimal test set first, or run dsymutil manually before running Valgrind?
> Change Valgrind to handle races better, > or run dsymutil manually before running Valgrind? Julian might know how feasible these are. > or run the shell under Valgrind once with a minimal test set first, Yeah, we could run the PGO tests similar to the current Linux tests. Do you mean the browser instead of the shell?
On Mac, there seems to be an even larger performance penalty. In single-threaded jit-tests, a run without --track-origins=yes takes ~1.8 days, but a Linux run with --track-origins=yes takes ~1.3 days. The upcoming work in bug 638219 to enable multithreaded testing for jit-tests should make things significantly faster, but this is probably only limited to Linux builds due to comment 1.