The hwloc_cpuset_next() will calculate the next cpu behind a given one.
Use hwloc_cpuset_first() and hwloc_cpuset_next() in hwloc_cpuset_foreach()
to sparsely iterate over a cpuset.
Regards,
Bert
---
doc/Makefile.am | 1 +
include/hwloc/cpuset.h | 9 ++++++---
include/hwloc/rename.h | 1 +
src/cpuset.c | 24 ++++++++++++++++++++++++
tests/hwloc_cpuset_first_last_weight.c | 28 +++++++++++++++++++++++++++-
5 files changed, 59 insertions(+), 4 deletions(-)
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 9c7bcf7..6fed82c 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -266,6 +266,7 @@ man3_MANS = \
$(DOX_MAN_DIR)/man3/hwloc_cpuset_isset.3 \
$(DOX_MAN_DIR)/man3/hwloc_cpuset_iszero.3 \
$(DOX_MAN_DIR)/man3/hwloc_cpuset_last.3 \
+ $(DOX_MAN_DIR)/man3/hwloc_cpuset_next.3 \
$(DOX_MAN_DIR)/man3/hwloc_cpuset_notset.3 \
$(DOX_MAN_DIR)/man3/hwloc_cpuset_orset.3 \
$(DOX_MAN_DIR)/man3/hwloc_cpuset_set.3 \
diff --git a/include/hwloc/cpuset.h b/include/hwloc/cpuset.h
index ad2dab4..5a629e9 100644
--- a/include/hwloc/cpuset.h
+++ b/include/hwloc/cpuset.h
@@ -156,6 +156,9 @@ HWLOC_DECLSPEC int hwloc_cpuset_first(hwloc_const_cpuset_t
set) __hwloc_attribut
/** \brief Compute the last CPU (most significant bit) in CPU set \p set */
HWLOC_DECLSPEC int hwloc_cpuset_last(hwloc_const_cpuset_t set)
__hwloc_attribute_pure;
+/** \brief Compute the next CPU in CPU set \p set which is after CPU \p
prev_cpu */
+HWLOC_DECLSPEC int hwloc_cpuset_next(hwloc_const_cpuset_t set, unsigned
prev_cpu) __hwloc_attribute_pure;
+
/** \brief Keep a single CPU among those set in CPU set \p set
*
* Might be used before binding so that the process does not
@@ -188,13 +191,13 @@ HWLOC_DECLSPEC int
hwloc_cpuset_weight(hwloc_const_cpuset_t set) __hwloc_attribu
*/
#define hwloc_cpuset_foreach_begin(cpu, set) \
do { \
- for (cpu = 0; cpu < HWLOC_NBMAXCPUS; cpu++) { \
- if (hwloc_cpuset_isset(set, cpu)) {
+ for (cpu = hwloc_cpuset_first(set); \
+ cpu != -1; \
+ cpu = hwloc_cpuset_next(set, cpu)) { \
/** \brief End of loop. Needs a terminating ';'.
*
* \sa hwloc_cpuset_foreach_begin */
#define hwloc_cpuset_foreach_end() \
- } \
} \
} while (0)
diff --git a/include/hwloc/rename.h b/include/hwloc/rename.h
index 6ebb454..bf1b600 100644
--- a/include/hwloc/rename.h
+++ b/include/hwloc/rename.h
@@ -165,6 +165,7 @@
#define hwloc_cpuset_notset HWLOC_NAME(cpuset_notset)
#define hwloc_cpuset_first HWLOC_NAME(cpuset_first)
#define hwloc_cpuset_last HWLOC_NAME(cpuset_last)
+#define hwloc_cpuset_next HWLOC_NAME(cpuset_next)
#define hwloc_cpuset_singlify HWLOC_NAME(cpuset_singlify)
#define hwloc_cpuset_compare_first HWLOC_NAME(cpuset_compare_first)
#define hwloc_cpuset_compare HWLOC_NAME(cpuset_compare)
diff --git a/src/cpuset.c b/src/cpuset.c
index 1787489..e2f9b16 100644
--- a/src/cpuset.c
+++ b/src/cpuset.c
@@ -510,6 +510,30 @@ int hwloc_cpuset_last(const struct hwloc_cpuset_s * set)
return -1;
}
+int hwloc_cpuset_next(const struct hwloc_cpuset_s * set, unsigned prev_cpu)
+{
+ int i = HWLOC_CPUSUBSET_INDEX(prev_cpu + 1);
+
+ HWLOC__CPUSET_CHECK(set);
+
+ for(; i<HWLOC_CPUSUBSET_COUNT; i++) {
+ unsigned long w = HWLOC_CPUSUBSET_SUBSET(*set,i);
+
+ /* if the prev cpu is in the same word as the possible next one,
+ we need to mask out previous cpus */
+ 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;
+ }
+
+ return -1;
+}
+
void hwloc_cpuset_singlify(struct hwloc_cpuset_s * set)
{
int i,found = 0;
diff --git a/tests/hwloc_cpuset_first_last_weight.c
b/tests/hwloc_cpuset_first_last_weight.c
index 093aea1..8a65d8e 100644
--- a/tests/hwloc_cpuset_first_last_weight.c
+++ b/tests/hwloc_cpuset_first_last_weight.c
@@ -8,22 +8,27 @@
#include <assert.h>
-/* check hwloc_cpuset_first(), _last() and _weight() */
+/* check hwloc_cpuset_first(), _last(), _next() and _weight() */
int main(void)
{
hwloc_cpuset_t set;
+ int i, cpu, expected_cpu;
/* empty set */
set = hwloc_cpuset_alloc();
assert(hwloc_cpuset_first(set) == -1);
assert(hwloc_cpuset_last(set) == -1);
+ assert(hwloc_cpuset_next(set, 0) == -1);
assert(hwloc_cpuset_weight(set) == 0);
/* full set */
hwloc_cpuset_fill(set);
assert(hwloc_cpuset_first(set) == 0);
assert(hwloc_cpuset_last(set) == HWLOC_NBMAXCPUS-1);
+ assert(hwloc_cpuset_next(set, 0) == 1);
+ assert(hwloc_cpuset_next(set, HWLOC_NBMAXCPUS-2) == HWLOC_NBMAXCPUS-1);
+ assert(hwloc_cpuset_next(set, HWLOC_NBMAXCPUS-1) == -1);
assert(hwloc_cpuset_weight(set) == HWLOC_NBMAXCPUS);
/* custom sets */
@@ -31,16 +36,37 @@ int main(void)
hwloc_cpuset_set_range(set, 36, 59);
assert(hwloc_cpuset_first(set) == 36);
assert(hwloc_cpuset_last(set) == 59);
+ assert(hwloc_cpuset_next(set, 0) == 36);
+ assert(hwloc_cpuset_next(set, 36) == 37);
+ assert(hwloc_cpuset_next(set, 59) == -1);
assert(hwloc_cpuset_weight(set) == 24);
hwloc_cpuset_set_range(set, 136, 259);
assert(hwloc_cpuset_first(set) == 36);
assert(hwloc_cpuset_last(set) == 259);
+ assert(hwloc_cpuset_next(set, 59) == 136);
+ assert(hwloc_cpuset_next(set, 259) == -1);
assert(hwloc_cpuset_weight(set) == 148);
hwloc_cpuset_clr(set, 199);
assert(hwloc_cpuset_first(set) == 36);
assert(hwloc_cpuset_last(set) == 259);
+ assert(hwloc_cpuset_next(set, 198) == 200);
+ assert(hwloc_cpuset_next(set, 199) == 200);
assert(hwloc_cpuset_weight(set) == 147);
+ i = 0;
+ hwloc_cpuset_foreach_begin(cpu, set) {
+ if (0 <= i && i < 24)
+ expected_cpu = i + 36;
+ else if (24 <= i && i < 87)
+ expected_cpu = i + 112;
+ else if (87 <= i && i < 147)
+ expected_cpu = i + 113;
+
+ assert(expected_cpu == cpu);
+
+ i++;
+ } hwloc_cpuset_foreach_end();
+
hwloc_cpuset_free(set);
return 0;
--
tg: (1926bee..) bw/sparse-cpuset-foreach (depends on:
bw/semi-colon-safe-foreach)
