https://github.com/python/cpython/commit/c45be8aa71ad886e12e8c897274498e4d828c9a5
commit: c45be8aa71ad886e12e8c897274498e4d828c9a5
branch: main
author: Diego Russo <diego.ru...@arm.com>
committer: brandtbucher <brandtbuc...@gmail.com>
date: 2024-11-11T17:20:10-08:00
summary:
GH-126195: Use M1 JIT memory protection APIs (GH-126196)
files:
A
Misc/NEWS.d/next/Core_and_Builtins/2024-10-30-18-16-10.gh-issue-126195.6ezBpr.rst
M Python/jit.c
diff --git
a/Misc/NEWS.d/next/Core_and_Builtins/2024-10-30-18-16-10.gh-issue-126195.6ezBpr.rst
b/Misc/NEWS.d/next/Core_and_Builtins/2024-10-30-18-16-10.gh-issue-126195.6ezBpr.rst
new file mode 100644
index 00000000000000..01424d8a545d78
--- /dev/null
+++
b/Misc/NEWS.d/next/Core_and_Builtins/2024-10-30-18-16-10.gh-issue-126195.6ezBpr.rst
@@ -0,0 +1 @@
+Improve JIT performance by 1.4% on macOS Apple Silicon by using
platform-specific memory protection APIs. Patch by Diego Russo.
diff --git a/Python/jit.c b/Python/jit.c
index 90f693dfb7c41b..7dd0da7a45055a 100644
--- a/Python/jit.c
+++ b/Python/jit.c
@@ -58,7 +58,12 @@ jit_alloc(size_t size)
int failed = memory == NULL;
#else
int flags = MAP_ANONYMOUS | MAP_PRIVATE;
- unsigned char *memory = mmap(NULL, size, PROT_READ | PROT_WRITE, flags,
-1, 0);
+ int prot = PROT_READ | PROT_WRITE;
+# ifdef MAP_JIT
+ flags |= MAP_JIT;
+ prot |= PROT_EXEC;
+# endif
+ unsigned char *memory = mmap(NULL, size, prot, flags, -1, 0);
int failed = memory == MAP_FAILED;
#endif
if (failed) {
@@ -102,8 +107,11 @@ mark_executable(unsigned char *memory, size_t size)
int old;
int failed = !VirtualProtect(memory, size, PAGE_EXECUTE_READ, &old);
#else
+ int failed = 0;
__builtin___clear_cache((char *)memory, (char *)memory + size);
- int failed = mprotect(memory, size, PROT_EXEC | PROT_READ);
+#ifndef MAP_JIT
+ failed = mprotect(memory, size, PROT_EXEC | PROT_READ);
+#endif
#endif
if (failed) {
jit_error("unable to protect executable memory");
@@ -499,6 +507,9 @@ _PyJIT_Compile(_PyExecutorObject *executor, const
_PyUOpInstruction trace[], siz
if (memory == NULL) {
return -1;
}
+#ifdef MAP_JIT
+ pthread_jit_write_protect_np(0);
+#endif
// Update the offsets of each instruction:
for (size_t i = 0; i < length; i++) {
state.instruction_starts[i] += (uintptr_t)memory;
@@ -529,6 +540,9 @@ _PyJIT_Compile(_PyExecutorObject *executor, const
_PyUOpInstruction trace[], siz
data += group->data_size;
assert(code == memory + code_size);
assert(data == memory + code_size + data_size);
+#ifdef MAP_JIT
+ pthread_jit_write_protect_np(1);
+#endif
if (mark_executable(memory, total_size)) {
jit_free(memory, total_size);
return -1;
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