diff options
author | Wilco Dijkstra <wdijkstr@arm.com> | 2019-05-17 18:16:20 +0100 |
---|---|---|
committer | Wilco Dijkstra <wdijkstr@arm.com> | 2019-05-17 18:16:20 +0100 |
commit | 1f50f2ad854c84ead522bfc7331b46dbe6057d53 (patch) | |
tree | a350b22461a9b819877711cf88a53f0191b388b5 /malloc | |
parent | fef7c63cd5a5a3150dc9465687359351afab5010 (diff) | |
download | glibc-1f50f2ad854c84ead522bfc7331b46dbe6057d53.zip glibc-1f50f2ad854c84ead522bfc7331b46dbe6057d53.tar.gz glibc-1f50f2ad854c84ead522bfc7331b46dbe6057d53.tar.bz2 |
Small tcache improvements
Change the tcache->counts[] entries to uint16_t - this removes
the limit set by char and allows a larger tcache. Remove a few
redundant asserts.
bench-malloc-thread with 4 threads is ~15% faster on Cortex-A72.
Reviewed-by: DJ Delorie <dj@redhat.com>
* malloc/malloc.c (MAX_TCACHE_COUNT): Increase to UINT16_MAX.
(tcache_put): Remove redundant assert.
(tcache_get): Remove redundant asserts.
(__libc_malloc): Check tcache count is not zero.
* manual/tunables.texi (glibc.malloc.tcache_count): Update maximum.
Diffstat (limited to 'malloc')
-rw-r--r-- | malloc/malloc.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c index b8baaa2..00ce48c 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -321,6 +321,10 @@ __malloc_assert (const char *assertion, const char *file, unsigned int line, /* This is another arbitrary limit, which tunables can change. Each tcache bin will hold at most this number of chunks. */ # define TCACHE_FILL_COUNT 7 + +/* Maximum chunks in tcache bins for tunables. This value must fit the range + of tcache->counts[] entries, else they may overflow. */ +# define MAX_TCACHE_COUNT UINT16_MAX #endif @@ -2901,12 +2905,10 @@ typedef struct tcache_entry time), this is for performance reasons. */ typedef struct tcache_perthread_struct { - char counts[TCACHE_MAX_BINS]; + uint16_t counts[TCACHE_MAX_BINS]; tcache_entry *entries[TCACHE_MAX_BINS]; } tcache_perthread_struct; -#define MAX_TCACHE_COUNT 127 /* Maximum value of counts[] entries. */ - static __thread bool tcache_shutting_down = false; static __thread tcache_perthread_struct *tcache = NULL; @@ -2916,7 +2918,6 @@ static __always_inline void tcache_put (mchunkptr chunk, size_t tc_idx) { tcache_entry *e = (tcache_entry *) chunk2mem (chunk); - assert (tc_idx < TCACHE_MAX_BINS); /* Mark this chunk as "in the tcache" so the test in _int_free will detect a double free. */ @@ -2933,8 +2934,6 @@ static __always_inline void * tcache_get (size_t tc_idx) { tcache_entry *e = tcache->entries[tc_idx]; - assert (tc_idx < TCACHE_MAX_BINS); - assert (tcache->counts[tc_idx] > 0); tcache->entries[tc_idx] = e->next; --(tcache->counts[tc_idx]); e->key = NULL; @@ -3046,9 +3045,8 @@ __libc_malloc (size_t bytes) DIAG_PUSH_NEEDS_COMMENT; if (tc_idx < mp_.tcache_bins - /*&& tc_idx < TCACHE_MAX_BINS*/ /* to appease gcc */ && tcache - && tcache->entries[tc_idx] != NULL) + && tcache->counts[tc_idx] > 0) { return tcache_get (tc_idx); } |