diff options
| author |   Len Brown <len.brown@intel.com> | 2020-05-27 00:38:38 -0400 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2020-09-03 13:48:07 -0400 |
| commit | d76bb7a09bb3b8711077912f3e80cfcf39cd9d0b (patch) | |
| tree | aeafcf2244683cab2c43bb238c4a8c4bc910bc96 /tools/power/x86/turbostat | |
| parent | x86/cpu: Add Lakefield, Alder Lake and Rocket Lake models to the to Intel CPU family (diff) | |
| download | linux-dev-d76bb7a09bb3b8711077912f3e80cfcf39cd9d0b.tar.xz linux-dev-d76bb7a09bb3b8711077912f3e80cfcf39cd9d0b.zip | |
tools/power turbostat: Print /dev/cpu_dma_latency
Users are puzzled when they use tuned performance and all their
C-states vanish. Dump /dev/cpu_dma_latency and state
whether the value is default, or constraining,
to explain this situation.
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'tools/power/x86/turbostat')
| -rw-r--r-- | tools/power/x86/turbostat/turbostat.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c index 33b370865d16..4c679568fda4 100644 --- a/tools/power/x86/turbostat/turbostat.c +++ b/tools/power/x86/turbostat/turbostat.c @@ -4698,6 +4698,32 @@ unsigned int intel_model_duplicates(unsigned int model) } return model; } + +void print_dev_latency(void) +{ + char *path = "/dev/cpu_dma_latency"; + int fd; + int value; + int retval; + + fd = open(path, O_RDONLY); + if (fd < 0) { + warn("fopen %s\n", path); + return; + } + + retval = read(fd, (void *)&value, sizeof(int)); + if (retval != sizeof(int)) { + warn("read %s\n", path); + close(fd); + return; + } + fprintf(outf, "/dev/cpu_dma_latency: %d usec (%s)\n", + value, value == 2000000000 ? "default" : "constrained"); + + close(fd); +} + void process_cpuid() { unsigned int eax, ebx, ecx, edx; @@ -4967,6 +4993,8 @@ void process_cpuid() dump_cstate_pstate_config_info(family, model); if (!quiet) + print_dev_latency(); + if (!quiet) dump_sysfs_cstate_config(); if (!quiet) dump_sysfs_pstate_config(); |