diff mbox series

[3/7] perf lock contention: Update default map size to 16384

Message ID 20230406210611.1622492-4-namhyung@kernel.org
State New
Headers
Series perf lock contention: Improve performance if map is full (v1) |

Commit Message

Namhyung Kim April 6, 2023, 9:06 p.m. UTC 
  The BPF hash map will align the map size to a power of 2.  So 10k would
be 16k anyway.  Let's have the actual size to avoid confusions.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/Documentation/perf-lock.txt         | 3 ++-
 tools/perf/builtin-lock.c                      | 2 +-
 tools/perf/util/bpf_skel/lock_contention.bpf.c | 5 +----
 tools/perf/util/bpf_skel/lock_data.h           | 3 +++
 4 files changed, 7 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/tools/perf/Documentation/perf-lock.txt b/tools/perf/Documentation/perf-lock.txt
index b5e5d088d51c..6e5ba3cd2b72 100644
--- a/tools/perf/Documentation/perf-lock.txt
+++ b/tools/perf/Documentation/perf-lock.txt
@@ -157,7 +157,8 @@  CONTENTION OPTIONS
 
 -M::
 --map-nr-entries=<value>::
-	Maximum number of BPF map entries (default: 10240).
+	Maximum number of BPF map entries (default: 16384).
+	This will be aligned to a power of 2.
 
 --max-stack=<value>::
 	Maximum stack depth when collecting lock contention (default: 8).
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index ef56bf90058d..9b92c7a5aefb 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -60,7 +60,7 @@  static bool show_thread_stats;
 static bool show_lock_addrs;
 static bool show_lock_owner;
 static bool use_bpf;
-static unsigned long bpf_map_entries = 10240;
+static unsigned long bpf_map_entries = MAX_ENTRIES;
 static int max_stack_depth = CONTENTION_STACK_DEPTH;
 static int stack_skip = CONTENTION_STACK_SKIP;
 static int print_nr_entries = INT_MAX / 2;
diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c
index 3f4ee3992e81..f9d2d792ccc8 100644
--- a/tools/perf/util/bpf_skel/lock_contention.bpf.c
+++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c
@@ -7,9 +7,6 @@ 
 
 #include "lock_data.h"
 
-/* default buffer size */
-#define MAX_ENTRIES  10240
-
 /* for collect_lock_syms().  4096 was rejected by the verifier */
 #define MAX_CPUS  1024
 
@@ -63,7 +60,7 @@  struct {
 	__uint(type, BPF_MAP_TYPE_HASH);
 	__uint(key_size, sizeof(__u64));
 	__uint(value_size, sizeof(__u32));
-	__uint(max_entries, 16384);
+	__uint(max_entries, MAX_ENTRIES);
 } lock_syms SEC(".maps");
 
 struct {
diff --git a/tools/perf/util/bpf_skel/lock_data.h b/tools/perf/util/bpf_skel/lock_data.h
index 1ba61cb4d480..260062a9f2ab 100644
--- a/tools/perf/util/bpf_skel/lock_data.h
+++ b/tools/perf/util/bpf_skel/lock_data.h
@@ -15,6 +15,9 @@  struct contention_task_data {
 	char comm[TASK_COMM_LEN];
 };
 
+/* default buffer size */
+#define MAX_ENTRIES  16384
+
 /*
  * Upper bits of the flags in the contention_data are used to identify
  * some well-known locks which do not have symbols (non-global locks).