Experimental configuration option for fast path prefetch from cache_bin

This commit is contained in:
Slobodan Predolac 2025-06-04 09:48:14 -07:00 committed by Guangli Dai
parent 9528a2e2dd
commit d73de95f72
3 changed files with 41 additions and 0 deletions

View file

@ -1434,6 +1434,36 @@ if test "x$enable_experimental_smallocx" = "x1" ; then
fi
AC_SUBST([enable_experimental_smallocx])
dnl Do not enable fastpath prefetch by default.
AC_ARG_ENABLE([experimental_fp_prefetch],
[AS_HELP_STRING([--enable-experimental-fp-prefetch], [Enable experimental fastpath prefetch])],
[if test "x$enable_experimental_fp_prefetch" = "xno" ; then
enable_experimental_fp_prefetch="0"
else
dnl Check if we have __builtin_prefetch.
JE_CFLAGS_SAVE()
JE_CFLAGS_ADD([-Werror=implicit-function-declaration])
JE_COMPILABLE([builtin prefetch], [], [
void foo(void *p) { __builtin_prefetch(p, 1, 3); }
],
[je_cv_have_builtin_prefetch])
if test "x${je_cv_have_builtin_prefetch}" = "xyes" ; then
enable_experimental_fp_prefetch="1"
else
enable_experimental_fp_prefetch="0"
AC_MSG_ERROR([--enable--experimental-fp-prefetch can only be used when builtin_preftech is available])
fi
JE_CFLAGS_RESTORE()
fi
],
[enable_experimental_fp_prefetch="0"]
)
if test "x$enable_experimental_fp_prefetch" = "x1" ; then
AC_DEFINE([JEMALLOC_EXPERIMENTAL_FASTPATH_PREFETCH], [ ], [ ])
fi
AC_SUBST([enable_experimental_fp_prefetch])
dnl Do not enable profiling by default.
AC_ARG_ENABLE([prof],
[AS_HELP_STRING([--enable-prof], [Enable allocation profiling])],

View file

@ -160,6 +160,11 @@
/* JEMALLOC_EXPERIMENTAL_SMALLOCX_API enables experimental smallocx API. */
#undef JEMALLOC_EXPERIMENTAL_SMALLOCX_API
/* JEMALLOC_EXPERIMENTAL_FASTPATH_PREFETCH enables prefetch
* on malloc fast path.
*/
#undef JEMALLOC_EXPERIMENTAL_FASTPATH_PREFETCH
/* JEMALLOC_PROF enables allocation profiling. */
#undef JEMALLOC_PROF

View file

@ -374,6 +374,12 @@ imalloc_fastpath(size_t size, void *(fallback_alloc)(size_t)) {
*/
ret = cache_bin_alloc_easy(bin, &tcache_success);
if (tcache_success) {
#if defined(JEMALLOC_EXPERIMENTAL_FASTPATH_PREFETCH)
cache_bin_sz_t lb = (cache_bin_sz_t)(uintptr_t)bin->stack_head;
if(likely(lb != bin->low_bits_empty)) {
util_prefetch_write_range(*(bin->stack_head), usize);
}
#endif
fastpath_success_finish(tsd, allocated_after, bin, ret);
return ret;
}