aganea marked 3 inline comments as done. aganea added a subscriber: respindola. aganea added a comment.
In D75153#1906580 <https://reviews.llvm.org/D75153#1906580>, @MaskRay wrote: > Does `taskset -c 0-3 lld -flavor ...` restrict the number of cores? > > cpu_set_t cpu; > sched_getaffinity(0, sizeof(cpu), &cpu); > CPU_COUNT(&cpu) Thanks for raising this! This does not seem to work (I currently only have WSL at hand, no real Linux machine). I don't think it worked before my patch. The current code in LLVM is written such as: (//note the "if" statement//) #if defined(HAVE_SCHED_GETAFFINITY) && defined(HAVE_CPU_COUNT) cpu_set_t Set; if (sched_getaffinity(0, sizeof(Set), &Set)) return CPU_COUNT(&Set); #endif The doc <https://linux.die.net/man/2/sched_getaffinity> for `sched_getaffinity` says: > On success, sched_setaffinity() and sched_getaffinity() return 0. On error, > -1 is returned, and errno is set appropriately. So it would always fall back to `std::thread::hardware_concurrency`, which apparently does not always take affinity into account, according to @respindola (please see rG8c0ff9508da5f02e8ce6580a126a2018c9bf702a <https://reviews.llvm.org/rG8c0ff9508da5f02e8ce6580a126a2018c9bf702a>). I'll write a follow-up patch to test affinity on Linux and Windows. ================ Comment at: llvm/include/llvm/Support/Threading.h:201 + /// hardware core is used. + inline ThreadPoolStrategy heavyweight_hardware_concurrency(StringRef Num) { + Optional<ThreadPoolStrategy> S = ---------------- abrachet wrote: > Nit: Remove `inline` > https://llvm.org/docs/CodingStandards.html#don-t-use-inline-when-defining-a-function-in-a-class-definition After discussing offling with @abrachet , I'll leave the `inline` for now. It makes the symbol weak, removing `inline` would otherwise fail linking. I can move the function(s) to the .CPP after this patch to save on link time. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D75153/new/ https://reviews.llvm.org/D75153 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
