[FFmpeg-devel] [PATCH] checkasm: add sample argument to adjust during bench

[J. Dekker]

Some timers on certain device and test combinations can produce noisy
results, affecting the reliability of performance measurements. One
notable example of this is the Canaan K230 RISC-V development board.

An option to adjust the number of samples (--samples) has been added,
allowing developers to increase or adjust the sample count for more
reliable results.

Signed-off-by: J. Dekker <jdek at itanimul.li>
---

 This could also be implemented as a compile time define or a configure
 argument.

 tests/checkasm/checkasm.c | 12 +++++++++++-
 tests/checkasm/checkasm.h |  4 ++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/tests/checkasm/checkasm.c b/tests/checkasm/checkasm.c
index ffc89882b1..c31adc3690 100644
--- a/tests/checkasm/checkasm.c
+++ b/tests/checkasm/checkasm.c
@@ -72,6 +72,9 @@
 void (*checkasm_checked_call)(void *func, int dummy, ...) = checkasm_checked_call_novfp;
 #endif
 
+/* Trade-off between speed and accuracy */
+uint64_t bench_runs = 1000;
+
 /* List of tests to invoke */
 static const struct {
     const char *name;
@@ -819,7 +822,7 @@ static void bench_uninit(void)
 static int usage(const char *path)
 {
     fprintf(stderr,
-            "Usage: %s [--bench] [--test=<pattern>] [--verbose] [seed]\n",
+            "Usage: %s [--bench] [--samples=<count>] [--test=<pattern>] [--verbose] [seed]\n",
             path);
     return 1;
 }
@@ -866,6 +869,13 @@ int main(int argc, char *argv[])
             state.test_name = arg + 7;
         } else if (!strcmp(arg, "--verbose") || !strcmp(arg, "-v")) {
             state.verbose = 1;
+        } else if (!strncmp(arg, "--samples=", 10)) {
+            l = strtoul(arg + 10, &end, 10);
+            if (*end == '\0') {
+                bench_runs = l;
+            } else {
+                return usage(argv[0]);
+            }
         } else if ((l = strtoul(arg, &end, 10)) <= UINT_MAX &&
                    *end == '\0') {
             seed = l;
diff --git a/tests/checkasm/checkasm.h b/tests/checkasm/checkasm.h
index 07fcc751ff..11f07a919f 100644
--- a/tests/checkasm/checkasm.h
+++ b/tests/checkasm/checkasm.h
@@ -167,7 +167,7 @@ extern AVLFG checkasm_lfg;
 
 static av_unused void *func_ref, *func_new;
 
-#define BENCH_RUNS 1000 /* Trade-off between accuracy and speed */
+extern uint64_t bench_runs;
 
 /* Decide whether or not the specified function needs to be tested */
 #define check_func(func, ...) (checkasm_save_context(), func_ref = checkasm_check_func((func_new = func), __VA_ARGS__))
@@ -339,7 +339,7 @@ typedef struct CheckasmPerf {
             int ti, tcount = 0;\
             uint64_t t = 0; \
             checkasm_set_signal_handler_state(1);\
-            for (ti = 0; ti < BENCH_RUNS; ti++) {\
+            for (ti = 0; ti < bench_runs; ti++) {\
                 PERF_START(t);\
                 tfunc(__VA_ARGS__);\
                 tfunc(__VA_ARGS__);\
-- 
2.42.0