diff options
Diffstat (limited to 'benchmarks/gem_syslatency.c')
| -rw-r--r-- | benchmarks/gem_syslatency.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/benchmarks/gem_syslatency.c b/benchmarks/gem_syslatency.c index 701b4362..bc513652 100644 --- a/benchmarks/gem_syslatency.c +++ b/benchmarks/gem_syslatency.c @@ -75,6 +75,16 @@ static void bind_cpu(pthread_t thread, int cpu) pthread_setaffinity_np(thread, sizeof(mask), &mask); } +static void force_low_latency(void) +{ + int32_t target = 0; + int fd = open("/dev/cpu_dma_latency", O_RDWR); + if (fd < 0 || write(fd, &target, sizeof(target)) < 0) + fprintf(stderr, + "Unable to prevent CPU sleeps and force low latency using /dev/cpu_dma_latency: %s\n", + strerror(errno)); +} + #define LOCAL_I915_EXEC_NO_RELOC (1<<11) #define LOCAL_I915_EXEC_HANDLE_LUT (1<<12) @@ -246,9 +256,11 @@ int main(int argc, char **argv) default: break; } - } + /* Prevent CPU sleeps so that busy and idle loads are consistent. */ + force_low_latency(); + busy = calloc(ncpus, sizeof(*busy)); if (enable_gem_sysbusy) { for (n = 0; n < ncpus; n++) { |