> On Nov 18, 2020, at 8:23 PM, Yonghong Song <yhs@xxxxxx> wrote:
[...]
>
> Cc: Song Liu <songliubraving@xxxxxx>
> Signed-off-by: Yonghong Song <yhs@xxxxxx>
> ---
> tools/bpf/bpftool/prog.c | 32 ++++++++++++++++++++++++++++++--
> 1 file changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> index acdb2c245f0a..e33f27b950a5 100644
> --- a/tools/bpf/bpftool/prog.c
> +++ b/tools/bpf/bpftool/prog.c
> @@ -1717,11 +1717,39 @@ struct profile_metric {
> .ratio_desc = "LLC misses per million insns",
> .ratio_mul = 1e6,
> },
> + {
> + .name = "itlb_misses",
> + .attr = {
> + .type = PERF_TYPE_HW_CACHE,
> + .config =
> + PERF_COUNT_HW_CACHE_ITLB |
> + (PERF_COUNT_HW_CACHE_OP_READ << 8) |
> + (PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
> + .exclude_user = 1
> + },
> + .ratio_metric = 2,
> + .ratio_desc = "itlb misses per million insns",
> + .ratio_mul = 1e6,
> + },
> + {
> + .name = "dtlb_misses",
> + .attr = {
> + .type = PERF_TYPE_HW_CACHE,
> + .config =
> + PERF_COUNT_HW_CACHE_DTLB |
> + (PERF_COUNT_HW_CACHE_OP_READ << 8) |
> + (PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
> + .exclude_user = 1
> + },
> + .ratio_metric = 2,
> + .ratio_desc = "dtlb misses per million insns",
> + .ratio_mul = 1e6,
> + },
> };
>
> static __u64 profile_total_count;
>
> -#define MAX_NUM_PROFILE_METRICS 4
> +#define MAX_NUM_PROFILE_METRICS 6
This change is not necessary. This is the max number of enabled metrics.
We don't stop the perf counters, each enabled metric adds some error to
the final reading. Therefore, we don't want to enable too many metrics
in the same run. If we don't have a use case for more metrics in one run,
let's keep the cap of 4 metrics.
If we do want to increase this, we should also increase MAX_NUM_MATRICS
in profiler.bpf.c.
Other than this,
Acked-by: Song Liu <songliubraving@xxxxxx>
Thanks!
