Having c++11, we can now use a handy function called
std::thread::hardware_concurrency.
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
Ready to be installed?
Thanks,
Martin
gcc/ChangeLog:
* lto-wrapper.c (cpuset_popcount): Remove.
(init_num_threads): Remove and use hardware_concurrency.
---
gcc/lto-wrapper.c | 113 ++--------------------------------------------
1 file changed, 5 insertions(+), 108 deletions(-)
diff --git a/gcc/lto-wrapper.c b/gcc/lto-wrapper.c
index 03a5922f8ea..ea68490163d 100644
--- a/gcc/lto-wrapper.c
+++ b/gcc/lto-wrapper.c
@@ -49,6 +49,8 @@ along with GCC; see the file COPYING3. If not see
#include "lto-section-names.h"
#include "collect-utils.h"
+#include <thread>
+
/* Environment variable, used for passing the names of offload targets from GCC
driver to lto-wrapper. */
#define OFFLOAD_TARGET_NAMES_ENV "OFFLOAD_TARGET_NAMES"
@@ -1199,113 +1201,6 @@ cmp_priority (const void *a, const void *b)
return *((const int *)b)-*((const int *)a);
}
-/* Number of CPUs that can be used for parallel LTRANS phase. */
-
-static unsigned long nthreads_var = 0;
-
-#ifdef HAVE_PTHREAD_AFFINITY_NP
-unsigned long cpuset_size;
-static unsigned long get_cpuset_size;
-cpu_set_t *cpusetp;
-
-unsigned long
-static cpuset_popcount (unsigned long cpusetsize, cpu_set_t *cpusetp)
-{
-#ifdef CPU_COUNT_S
- /* glibc 2.7 and above provide a macro for this. */
- return CPU_COUNT_S (cpusetsize, cpusetp);
-#else
-#ifdef CPU_COUNT
- if (cpusetsize == sizeof (cpu_set_t))
- /* glibc 2.6 and above provide a macro for this. */
- return CPU_COUNT (cpusetp);
-#endif
- size_t i;
- unsigned long ret = 0;
- STATIC_ASSERT (sizeof (cpusetp->__bits[0]) == sizeof (unsigned long int));
- for (i = 0; i < cpusetsize / sizeof (cpusetp->__bits[0]); i++)
- {
- unsigned long int mask = cpusetp->__bits[i];
- if (mask == 0)
- continue;
- ret += __builtin_popcountl (mask);
- }
- return ret;
-#endif
-}
-#endif
-
-/* At startup, determine the default number of threads. It would seem
- this should be related to the number of cpus online. */
-
-static void
-init_num_threads (void)
-{
-#ifdef HAVE_PTHREAD_AFFINITY_NP
-#if defined (_SC_NPROCESSORS_CONF) && defined (CPU_ALLOC_SIZE)
- cpuset_size = sysconf (_SC_NPROCESSORS_CONF);
- cpuset_size = CPU_ALLOC_SIZE (cpuset_size);
-#else
- cpuset_size = sizeof (cpu_set_t);
-#endif
-
- cpusetp = (cpu_set_t *) xmalloc (gomp_cpuset_size);
- do
- {
- int ret = pthread_getaffinity_np (pthread_self (), gomp_cpuset_size,
- cpusetp);
- if (ret == 0)
- {
- /* Count only the CPUs this process can use. */
- nthreads_var = cpuset_popcount (cpuset_size, cpusetp);
- if (nthreads_var == 0)
- break;
- get_cpuset_size = cpuset_size;
-#ifdef CPU_ALLOC_SIZE
- unsigned long i;
- for (i = cpuset_size * 8; i; i--)
- if (CPU_ISSET_S (i - 1, cpuset_size, cpusetp))
- break;
- cpuset_size = CPU_ALLOC_SIZE (i);
-#endif
- return;
- }
- if (ret != EINVAL)
- break;
-#ifdef CPU_ALLOC_SIZE
- if (cpuset_size < sizeof (cpu_set_t))
- cpuset_size = sizeof (cpu_set_t);
- else
- cpuset_size = cpuset_size * 2;
- if (cpuset_size < 8 * sizeof (cpu_set_t))
- cpusetp
- = (cpu_set_t *) realloc (cpusetp, cpuset_size);
- else
- {
- /* Avoid fatal if too large memory allocation would be
- requested, e.g. kernel returning EINVAL all the time. */
- void *p = realloc (cpusetp, cpuset_size);
- if (p == NULL)
- break;
- cpusetp = (cpu_set_t *) p;
- }
-#else
- break;
-#endif
- }
- while (1);
- cpuset_size = 0;
- nthreads_var = 1;
- free (cpusetp);
- cpusetp = NULL;
-#endif
-#ifdef _SC_NPROCESSORS_ONLN
- nthreads_var = sysconf (_SC_NPROCESSORS_ONLN);
-#endif
-}
-
-/* FIXME: once using -std=c++11, we can use std::thread::hardware_concurrency.
*/
-
/* Test and return reason why a jobserver cannot be detected. */
static const char *
@@ -1389,6 +1284,9 @@ run_gcc (unsigned argc, char *argv[])
const char *incoming_dumppfx = dumppfx = NULL;
static char current_dir[] = { '.', DIR_SEPARATOR, '\0' };
+ /* Number of CPUs that can be used for parallel LTRANS phase. */
+ unsigned long nthreads_var = std::thread::hardware_concurrency ();
+
/* Get the driver and options. */
collect_gcc = getenv ("COLLECT_GCC");
if (!collect_gcc)
@@ -1779,7 +1677,6 @@ cont1:
else if (auto_parallel)
{
char buf[256];
- init_num_threads ();
if (nthreads_var == 0)
nthreads_var = 1;
if (verbose)
--
2.31.1
