Testing if a word does have any bit set should be considered less expansive
than calling ffsl/flsl first and than test this.
Regards,
Bert
---
src/cpuset.c | 44 +++++++++++++++++++++++---------------------
1 files changed, 23 insertions(+), 21 deletions(-)
diff --git a/src/cpuset.c b/src/cpuset.c
index bb23b47..f963c39 100644
--- a/src/cpuset.c
+++ b/src/cpuset.c
@@ -486,9 +486,9 @@ int hwloc_cpuset_first(const struct hwloc_cpuset_s * set)
for(i=0; i<HWLOC_CPUSUBSET_COUNT; i++) {
/* subsets are unsigned longs, use ffsl */
- int _ffs = hwloc_ffsl(HWLOC_CPUSUBSET_SUBSET(*set,i));
- if (_ffs>0)
- return _ffs - 1 + HWLOC_CPUSUBSET_SIZE*i;
+ unsigned long w = HWLOC_CPUSUBSET_SUBSET(*set,i);
+ if (w)
+ return hwloc_ffsl(w) - 1 + HWLOC_CPUSUBSET_SIZE*i;
}
return -1;
@@ -502,9 +502,9 @@ int hwloc_cpuset_last(const struct hwloc_cpuset_s * set)
for(i=HWLOC_CPUSUBSET_COUNT-1; i>=0; i--) {
/* subsets are unsigned longs, use flsl */
- int _fls = hwloc_flsl(HWLOC_CPUSUBSET_SUBSET(*set,i));
- if (_fls>0)
- return _fls - 1 + HWLOC_CPUSUBSET_SIZE*i;
+ unsigned long w = HWLOC_CPUSUBSET_SUBSET(*set,i);
+ if (w)
+ return hwloc_flsl(w) - 1 + HWLOC_CPUSUBSET_SIZE*i;
}
return -1;
@@ -517,6 +517,7 @@ int hwloc_cpuset_next(const struct hwloc_cpuset_s * set,
unsigned prev_cpu)
HWLOC__CPUSET_CHECK(set);
for(; i<HWLOC_CPUSUBSET_COUNT; i++) {
+ /* subsets are unsigned longs, use ffsl */
unsigned long w = HWLOC_CPUSUBSET_SUBSET(*set,i);
/* if the prev cpu is in the same word as the possible next one,
@@ -524,10 +525,8 @@ int hwloc_cpuset_next(const struct hwloc_cpuset_s * set,
unsigned prev_cpu)
if (HWLOC_CPUSUBSET_INDEX(prev_cpu) == i)
w &= ~((HWLOC_CPUSUBSET_VAL(prev_cpu) << 1) - 1);
- /* subsets are unsigned longs, use ffsl */
- int _ffs = hwloc_ffsl(w);
- if (_ffs>0)
- return _ffs - 1 + HWLOC_CPUSUBSET_SIZE*i;
+ if (w)
+ return hwloc_ffsl(w) - 1 + HWLOC_CPUSUBSET_SIZE*i;
}
return -1;
@@ -545,8 +544,9 @@ void hwloc_cpuset_singlify(struct hwloc_cpuset_s * set)
continue;
} else {
/* subsets are unsigned longs, use ffsl */
- int _ffs = hwloc_ffsl(HWLOC_CPUSUBSET_SUBSET(*set,i));
- if (_ffs>0) {
+ unsigned long w = HWLOC_CPUSUBSET_SUBSET(*set,i);
+ if (w) {
+ int _ffs = hwloc_ffsl(w);
HWLOC_CPUSUBSET_SUBSET(*set,i) =
HWLOC_CPUSUBSET_VAL(_ffs-1);
found = 1;
}
@@ -562,15 +562,17 @@ int hwloc_cpuset_compare_first(const struct
hwloc_cpuset_s * set1, const struct
HWLOC__CPUSET_CHECK(set2);
for(i=0; i<HWLOC_CPUSUBSET_COUNT; i++) {
- int _ffs1 = hwloc_ffsl(HWLOC_CPUSUBSET_SUBSET(*set1,i));
- int _ffs2 = hwloc_ffsl(HWLOC_CPUSUBSET_SUBSET(*set2,i));
- if (!_ffs1 && !_ffs2)
- continue;
- /* if both have a bit set, compare for real */
- if (_ffs1 && _ffs2)
- return _ffs1-_ffs2;
- /* one is empty, and it is considered higher, so
reverse-compare them */
- return _ffs2-_ffs1;
+ unsigned long w1 = HWLOC_CPUSUBSET_SUBSET(*set1,i);
+ unsigned long w2 = HWLOC_CPUSUBSET_SUBSET(*set2,i);
+ if (w1 || w2) {
+ int _ffs1 = hwloc_ffsl(HWLOC_CPUSUBSET_SUBSET(*set1,i));
+ int _ffs2 = hwloc_ffsl(HWLOC_CPUSUBSET_SUBSET(*set2,i));
+ /* if both have a bit set, compare for real */
+ if (_ffs1 && _ffs2)
+ return _ffs1-_ffs2;
+ /* one is empty, and it is considered higher, so
reverse-compare them */
+ return _ffs2-_ffs1;
+ }
}
return 0;
}
--
tg: (5b4ea2a..) bw/branch-for-ffsl (depends on: master)
