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perf lock contention: Simplify spinlock check 

The LCB_F_SPIN bit is used for spinlock, rwlock and optimistic spinning
in mutex.  In get_tstamp_elem() it needs to check spinlock and rwlock
only.  As mutex sets the LCB_F_MUTEX, it can check those two bits and
reduce the number of operations.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20240830065150.1758962-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
pull/960/head
Namhyung Kim 2024-08-29 23:51:49 -07:00 committed by Arnaldo Carvalho de Melo
parent 10d6c57c82
commit 05a5dd1dfd
1 changed files with 1 additions and 2 deletions
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3
tools/perf/util/bpf_skel/lock_contention.bpf.c
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@ -323,8 +323,7 @@ static inline struct tstamp_data *get_tstamp_elem(__u32 flags)
struct tstamp_data *pelem;
/* Use per-cpu array map for spinlock and rwlock */
if (flags == (LCB_F_SPIN | LCB_F_READ) || flags == LCB_F_SPIN ||
flags == (LCB_F_SPIN | LCB_F_WRITE)) {
if ((flags & (LCB_F_SPIN | LCB_F_MUTEX)) == LCB_F_SPIN) {
__u32 idx = 0;
pelem = bpf_map_lookup_elem(&tstamp_cpu, &idx);