[PATCH 4/9] tools: sync bitmap_weight() usage with the kernel

Yury Norov
2021-11-28T03:59:33Z

bitmap_weight() counts all set bits in the bitmap unconditionally.
However in some cases we can traverse a part of bitmap when we
only need to check if number of set bits is greater, less or equal
to some number.

This patch adds bitmap_weight_{eq,gt,le}, reimplements bitmap_{empty,full}
and replace bitmap_weight() where appropriate.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
tools/include/linux/bitmap.h | 42 +++++++++++++++++++------
tools/lib/bitmap.c | 60 ++++++++++++++++++++++++++++++++++++
tools/perf/builtin-c2c.c | 4 +--
tools/perf/util/pmu.c | 2 +-
4 files changed, 96 insertions(+), 12 deletions(-)

diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h
index ea97804d04d4..eb2831f7e5a7 100644
--- a/tools/include/linux/bitmap.h
+++ b/tools/include/linux/bitmap.h
@@ -12,6 +12,9 @@
unsigned long name[BITS_TO_LONGS(bits)]

int __bitmap_weight(const unsigned long *bitmap, int bits);
+bool __bitmap_weight_eq(const unsigned long *bitmap, unsigned int nbits, unsigned int num);
+bool __bitmap_weight_gt(const unsigned long *bitmap, unsigned int nbits, unsigned int num);
+bool __bitmap_weight_le(const unsigned long *bitmap, unsigned int nbits, unsigned int num);
void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits);
int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
@@ -45,27 +48,48 @@ static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
}

-static inline int bitmap_empty(const unsigned long *src, unsigned nbits)
+static inline int bitmap_weight(const unsigned long *src, unsigned int nbits)
{
if (small_const_nbits(nbits))
- return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
+ return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
+ return __bitmap_weight(src, nbits);
+}

- return find_first_bit(src, nbits) == nbits;
+static __always_inline bool bitmap_weight_eq(const unsigned long *src,
+ unsigned int nbits, unsigned int num)
+{
+ if (small_const_nbits(nbits))
+ return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits)) == num;
+
+ return __bitmap_weight_eq(src, nbits, num);
}

-static inline int bitmap_full(const unsigned long *src, unsigned int nbits)
+static __always_inline bool bitmap_weight_gt(const unsigned long *src,
+ unsigned int nbits, unsigned int num)
{
if (small_const_nbits(nbits))
- return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
+ return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits)) > num;

- return find_first_zero_bit(src, nbits) == nbits;
+ return __bitmap_weight_gt(src, nbits, num);
}

-static inline int bitmap_weight(const unsigned long *src, unsigned int nbits)
+static __always_inline bool bitmap_weight_le(const unsigned long *src,
+ unsigned int nbits, unsigned int num)
{
if (small_const_nbits(nbits))
- return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
- return __bitmap_weight(src, nbits);
+ return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits)) < num;
+
+ return __bitmap_weight_le(src, nbits, num);
+}
+
+static __always_inline bool bitmap_empty(const unsigned long *src, unsigned int nbits)
+{
+ return bitmap_weight_eq(src, nbits, 0);
+}
+
+static __always_inline bool bitmap_full(const unsigned long *src, unsigned int nbits)
+{
+ return bitmap_weight_eq(src, nbits, nbits);
}

static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
diff --git a/tools/lib/bitmap.c b/tools/lib/bitmap.c
index db466ef7be9d..3aaf1767d237 100644
--- a/tools/lib/bitmap.c
+++ b/tools/lib/bitmap.c
@@ -18,6 +18,66 @@ int __bitmap_weight(const unsigned long *bitmap, int bits)
return w;
}

+bool __bitmap_weight_eq(const unsigned long *bitmap, unsigned int bits, unsigned int num)
+{
+ unsigned int k, w, lim = bits / BITS_PER_LONG;
+
+ for (k = 0, w = 0; k < lim; k++) {
+ if (w + bits - k * BITS_PER_LONG < num)
+ return false;
+
+ w += hweight_long(bitmap[k]);
+
+ if (w > num)
+ return false;
+ }
+
+ if (bits % BITS_PER_LONG)
+ w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
+
+ return w == num;
+}
+
+bool __bitmap_weight_gt(const unsigned long *bitmap, unsigned int bits, unsigned int num)
+{
+ unsigned int k, w, lim = bits / BITS_PER_LONG;
+
+ for (k = 0, w = 0; k < lim; k++) {
+ if (w + bits - k * BITS_PER_LONG <= num)
+ return false;
+
+ w += hweight_long(bitmap[k]);
+
+ if (w > num)
+ return true;
+ }
+
+ if (bits % BITS_PER_LONG)
+ w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
+
+ return w > num;
+}
+
+bool __bitmap_weight_le(const unsigned long *bitmap, unsigned int bits, unsigned int num)
+{
+ unsigned int k, w, lim = bits / BITS_PER_LONG;
+
+ for (k = 0, w = 0; k < lim; k++) {
+ if (w + bits - k * BITS_PER_LONG < num)
+ return true;
+
+ w += hweight_long(bitmap[k]);
+
+ if (w >= num)
+ return false;
+ }
+
+ if (bits % BITS_PER_LONG)
+ w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
+
+ return w < num;
+}
+
void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index b5c67ef73862..51997386fb31 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -1080,7 +1080,7 @@ node_entry(struct perf_hpp_fmt *fmt __maybe_unused, struct perf_hpp *hpp,
bitmap_zero(set, c2c.cpus_cnt);
bitmap_and(set, c2c_he->cpuset, c2c.nodes[node], c2c.cpus_cnt);

- if (!bitmap_weight(set, c2c.cpus_cnt)) {
+ if (bitmap_empty(set, c2c.cpus_cnt)) {
if (c2c.node_info == 1) {
ret = scnprintf(hpp->buf, hpp->size, "%21s", " ");
advance_hpp(hpp, ret);
@@ -1944,7 +1944,7 @@ static int set_nodestr(struct c2c_hist_entry *c2c_he)
if (c2c_he->nodestr)
return 0;

- if (bitmap_weight(c2c_he->nodeset, c2c.nodes_cnt)) {
+ if (!bitmap_empty(c2c_he->nodeset, c2c.nodes_cnt)) {
len = bitmap_scnprintf(c2c_he->nodeset, c2c.nodes_cnt,
buf, sizeof(buf));
} else {
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 6ae58406f4fc..015ee1321c7c 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -1314,7 +1314,7 @@ static int pmu_config_term(const char *pmu_name,
*/
if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
if (term->no_value &&
- bitmap_weight(format->bits, PERF_PMU_FORMAT_BITS) > 1) {
+ bitmap_weight_gt(format->bits, PERF_PMU_FORMAT_BITS, 1)) {
if (err) {
parse_events_error__handle(err, term->err_val,
strdup("no value assigned for term"),
--
2.25.1