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[BOLT][Instrumentation] Don't share counters when using append-pid

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The point of append-pid option is to record separate profiles for
separate forks, which is impossible when counters are the same for
every process. It leads to a sum of all profiles in every file, plus
GlobalWriteProfileMutex located in a shared memory prevents some
processes from dumping their data at all.

Reviewed By: rafauler, Amir
Differential Revision: https://reviews.llvm.org/D153771
This commit is contained in:
Denis Revunov 2023-06-15 15:43:04 +00:00 committed by Denis Revunov
parent 8f7c53ef81
commit 02c3724d43
1 changed files with 11 additions and 7 deletions
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18
bolt/runtime/instr.cpp
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@ -1541,6 +1541,9 @@ extern "C" void __bolt_instr_indirect_tailcall();
/// Initialization code
extern "C" void __attribute((force_align_arg_pointer)) __bolt_instr_setup() {
__bolt_ind_call_counter_func_pointer = __bolt_instr_indirect_call;
__bolt_ind_tailcall_counter_func_pointer = __bolt_instr_indirect_tailcall;
const uint64_t CountersStart =
reinterpret_cast<uint64_t>(&__bolt_instr_locations[0]);
const uint64_t CountersEnd = alignTo(
@ -1548,18 +1551,19 @@ extern "C" void __attribute((force_align_arg_pointer)) __bolt_instr_setup() {
0x1000);
DEBUG(reportNumber("replace mmap start: ", CountersStart, 16));
DEBUG(reportNumber("replace mmap stop: ", CountersEnd, 16));
assert (CountersEnd > CountersStart, "no counters");
// Maps our counters to be shared instead of private, so we keep counting for
// forked processes
assert(CountersEnd > CountersStart, "no counters");
const bool Shared = !__bolt_instr_use_pid;
const uint64_t MapPrivateOrShared = Shared ? MAP_SHARED : MAP_PRIVATE;
void *Ret =
__mmap(CountersStart, CountersEnd - CountersStart, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_SHARED | MAP_FIXED, -1, 0);
MAP_ANONYMOUS | MapPrivateOrShared | MAP_FIXED, -1, 0);
assert(Ret != MAP_FAILED, "__bolt_instr_setup: Failed to mmap counters!");
__bolt_ind_call_counter_func_pointer = __bolt_instr_indirect_call;
__bolt_ind_tailcall_counter_func_pointer = __bolt_instr_indirect_tailcall;
// Conservatively reserve 100MiB shared pages
GlobalAlloc.setMaxSize(0x6400000);
GlobalAlloc.setShared(true);
GlobalAlloc.setShared(Shared);
GlobalWriteProfileMutex = new (GlobalAlloc, 0) Mutex();
if (__bolt_instr_num_ind_calls > 0)
GlobalIndCallCounters =