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| author |   Song Liu <songliubraving@fb.com> | 2020-04-30 00:15:04 -0700 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2020-05-01 10:36:32 -0700 |
| commit | d46edd671a147032e22cfeb271a5734703093649 (patch) | |
| tree | eee3bc7ad6740e4115f5df017b375ea8ea974829 /include/linux | |
| parent | selftests/bpf: Test allowed maps for bpf_sk_select_reuseport (diff) | |
| download | wireguard-linux-d46edd671a147032e22cfeb271a5734703093649.tar.xz wireguard-linux-d46edd671a147032e22cfeb271a5734703093649.zip | |
bpf: Sharing bpf runtime stats with BPF_ENABLE_STATS
Currently, sysctl kernel.bpf_stats_enabled controls BPF runtime stats.
Typical userspace tools use kernel.bpf_stats_enabled as follows:
1. Enable kernel.bpf_stats_enabled;
2. Check program run_time_ns;
3. Sleep for the monitoring period;
4. Check program run_time_ns again, calculate the difference;
5. Disable kernel.bpf_stats_enabled.
The problem with this approach is that only one userspace tool can toggle
this sysctl. If multiple tools toggle the sysctl at the same time, the
measurement may be inaccurate.
To fix this problem while keep backward compatibility, introduce a new
bpf command BPF_ENABLE_STATS. On success, this command enables stats and
returns a valid fd. BPF_ENABLE_STATS takes argument "type". Currently,
only one type, BPF_STATS_RUN_TIME, is supported. We can extend the
command to support other types of stats in the future.
With BPF_ENABLE_STATS, user space tool would have the following flow:
1. Get a fd with BPF_ENABLE_STATS, and make sure it is valid;
2. Check program run_time_ns;
3. Sleep for the monitoring period;
4. Check program run_time_ns again, calculate the difference;
5. Close the fd.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200430071506.1408910-2-songliubraving@fb.com
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/bpf.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index c07b1d2f3824..1262ec460ab3 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -987,6 +987,7 @@ _out: \ #ifdef CONFIG_BPF_SYSCALL DECLARE_PER_CPU(int, bpf_prog_active); +extern struct mutex bpf_stats_enabled_mutex; /* * Block execution of BPF programs attached to instrumentation (perf, |