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Subject[patch 7/7] perf/bench/futex-hash: Support preallocate hash table
Instead of using the default hash size on the first allocation it is
possible to allocate a specific number of slots upfront.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
tools/perf/bench/futex-hash.c | 16 ++++++++++++++--
tools/perf/bench/futex.h | 5 +++++
2 files changed, 19 insertions(+), 2 deletions(-)

--- a/tools/perf/bench/futex-hash.c
+++ b/tools/perf/bench/futex-hash.c
@@ -30,6 +30,7 @@ static unsigned int nsecs = 10;
static unsigned int nfutexes = 1024;
static bool fshared = false, done = false, silent = false;
static int futex_flag = 0;
+static unsigned int prealloc;
static int numa_node = -1;

struct timeval start, end, runtime;
@@ -51,6 +52,7 @@ static const struct option options[] = {
OPT_UINTEGER('f', "futexes", &nfutexes, "Specify amount of futexes per threads"),
OPT_BOOLEAN( 's', "silent", &silent, "Silent mode: do not display data/details"),
OPT_BOOLEAN( 'S', "shared", &fshared, "Use shared futexes instead of private ones"),
+ OPT_UINTEGER('p', "prealloc",&prealloc, "Specify number of preallocated hash slots"),
#ifdef CONFIG_NUMA
OPT_INTEGER( 'n', "numa", &numa_node, "Specify the NUMA node"),
#endif
@@ -138,6 +140,7 @@ int bench_futex_hash(int argc, const cha
unsigned int i, ncpus;
pthread_attr_t thread_attr;
struct worker *worker = NULL;
+ char *prealloc_str = NULL;
char *node_str = NULL;
unsigned int cpunum;

@@ -192,11 +195,20 @@ int bench_futex_hash(int argc, const cha
if (!fshared)
futex_flag = FUTEX_PRIVATE_FLAG;

- printf("Run summary [PID %d]: %d threads%s, each operating on %d [%s] futexes for %d secs.\n\n",
+ if (prealloc) {
+ ret = futex_preallocate(prealloc);
+ if (ret < 0)
+ err(EXIT_FAILURE, "futex_prealloate");
+ ret = asprintf(&prealloc_str, " P %u %d", prealloc, ret);
+ if (ret < 0)
+ err(EXIT_FAILURE, "futex_preallocate, asprintf");
+ }
+
+ printf("Run summary [PID %d]: %d threads%s, each operating on %d [%s%s] futexes for %d secs.\n\n",
getpid(), nthreads,
node_str ? : "",
nfutexes, fshared ? "shared":"private",
- nsecs);
+ prealloc_str ? : "", nsecs);

init_stats(&throughput_stats);
pthread_mutex_init(&thread_lock, NULL);
--- a/tools/perf/bench/futex.h
+++ b/tools/perf/bench/futex.h
@@ -101,4 +101,9 @@ static inline int pthread_attr_setaffini
}
#endif

+static inline int futex_preallocate(u_int32_t hash_size)
+{
+ return futex(0, FUTEX_PREALLOC_HASH, hash_size, NULL, NULL, 0, 0);
+}
+
#endif /* _FUTEX_H */
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