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Dave Marchevsky 2b4b2621fd selftests/bpf: Add benchmark for local_storage RCU Tasks Trace usage

This benchmark measures grace period latency and kthread cpu usage of
RCU Tasks Trace when many processes are creating/deleting BPF
local_storage. Intent here is to quantify improvement on these metrics
after Paul's recent RCU Tasks patches [0].

Specifically, fork 15k tasks which call a bpf prog that creates/destroys
task local_storage and sleep in a loop, resulting in many
call_rcu_tasks_trace calls.

To determine grace period latency, trace time elapsed between
rcu_tasks_trace_pregp_step and rcu_tasks_trace_postgp; for cpu usage
look at rcu_task_trace_kthread's stime in /proc/PID/stat.

On my virtualized test environment (Skylake, 8 cpus) benchmark results
demonstrate significant improvement:

BEFORE Paul's patches:

  SUMMARY tasks_trace grace period latency        avg 22298.551 us stddev 1302.165 us
  SUMMARY ticks per tasks_trace grace period      avg 2.291 stddev 0.324

AFTER Paul's patches:

  SUMMARY tasks_trace grace period latency        avg 16969.197 us  stddev 2525.053 us
  SUMMARY ticks per tasks_trace grace period      avg 1.146 stddev 0.178

Note that since these patches are not in bpf-next benchmarking was done
by cherry-picking this patch onto rcu tree.

  [0] https://lore.kernel.org/rcu/20220620225402.GA3842369@paulmck-ThinkPad-P17-Gen-1/

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220705190018.3239050-1-davemarchevsky@fb.com

2022-07-07 16:35:21 +02:00

bench_bloom_filter_map.c

selftests/bpf: Fix a tautological-constant-out-of-range-compare compiler warning

2021-11-12 14:11:46 -08:00

bench_bpf_hashmap_full_update.c

selftest/bpf/benchs: Add bpf_map benchmark

2022-06-11 14:25:35 -07:00

bench_bpf_loop.c

selftest/bpf/benchs: Add bpf_loop benchmark

2021-11-30 10:56:28 -08:00

bench_count.c

selftests/bpf: Fix checkpatch error on empty function parameter