[PATCH bpf-next v2] bpftool: add {i,d}tlb_misses support for bpftool profile

[PATCH bpf-next v2] bpftool: add {i,d}tlb_misses support for bpftool profile

[Yonghong Song]

Commit 47c09d6a9f67("bpftool: Introduce "prog profile" command")
introduced "bpftool prog profile" command which can be used
to profile bpf program with metrics like # of instructions,

This patch added support for itlb_misses and dtlb_misses.
During an internal bpf program performance evaluation,
I found these two metrics are also very useful. The following
is an example output:

 $ bpftool prog profile id 324 duration 3 cycles itlb_misses

           1885029 run_cnt
        5134686073 cycles
            306893 itlb_misses
 $ bpftool prog profile id 324 duration 3 cycles dtlb_misses

           1827382 run_cnt
        4943593648 cycles
           5975636 dtlb_misses
 $ bpftool prog profile id 324 duration 3 cycles llc_misses

           1836527 run_cnt
        5019612972 cycles
           4161041 llc_misses

From the above, we can see quite some dtlb misses, 3 dtlb misses
perf prog run. This might be something worth further investigation.

Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
 tools/bpf/bpftool/prog.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

changelog:
  v1 -> v2:
    - dropped the change for macro MAX_NUM_PROFILE_METRICS 
      as (1). the change is incomplete and bpf program change is also
      needed, and (2). increasing MAX_NUM_PROFILE_METRICS may cause
      more measurement inaccuracy and this patch is not for such a
      usecase.

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index acdb2c245f0a..1fe3ba255bad 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1717,6 +1717,34 @@ 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;
@@ -2109,7 +2137,7 @@ static int do_help(int argc, char **argv)
 		"                 struct_ops | fentry | fexit | freplace | sk_lookup }\n"
 		"       ATTACH_TYPE := { msg_verdict | stream_verdict | stream_parser |\n"
 		"                        flow_dissector }\n"
-		"       METRIC := { cycles | instructions | l1d_loads | llc_misses }\n"
+		"       METRIC := { cycles | instructions | l1d_loads | llc_misses | itlb_misses | dtlb_misses }\n"
 		"       " HELP_SPEC_OPTIONS "\n"
 		"",
 		bin_name, argv[-2]);
-- 
2.24.1

Re: [PATCH bpf-next v2] bpftool: add {i,d}tlb_misses support for bpftool profile

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (refs/heads/master):

On Wed, 18 Nov 2020 23:30:39 -0800 you wrote:
> Commit 47c09d6a9f67("bpftool: Introduce "prog profile" command")
> introduced "bpftool prog profile" command which can be used
> to profile bpf program with metrics like # of instructions,
> 
> This patch added support for itlb_misses and dtlb_misses.
> During an internal bpf program performance evaluation,
> I found these two metrics are also very useful. The following
> is an example output:
> 
> [...]

Here is the summary with links:
  - [bpf-next,v2] bpftool: add {i,d}tlb_misses support for bpftool profile
    https://git.kernel.org/bpf/bpf-next/c/450d060e8f75

You are awesome, thank you!
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