Commit 05a5dd1d authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
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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: default avatarNamhyung 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 10d6c57c

tools/perf/util/bpf_skel/lock_contention.bpf.c

+1 −2
Original line number Diff line number Diff line
@@ -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);