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08158c111d
Add a reusable timing library for BPF benchmarks that need to measure BPF program execution time. The BPF side (progs/bench_bpf_timing.bpf.h) provides per-CPU sample arrays and BENCH_BPF_LOOP(), a macro that brackets batch_iters iterations with bpf_ktime_get_ns() reads and records the elapsed time. One extra untimed iteration runs afterward for output validation. The userspace side (benchs/bench_bpf_timing.c) collects samples from the skeleton BSS, computes percentile statistics, and auto-calibrates batch_iters to target ~10 ms per batch. Signed-off-by: Puranjay Mohan <puranjay@kernel.org> Link: https://lore.kernel.org/r/20260427232313.1582588-3-puranjay@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
51 lines
1.5 KiB
C
51 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
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#ifndef __BENCH_BPF_TIMING_H__
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#define __BENCH_BPF_TIMING_H__
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#include <stdbool.h>
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#include <linux/types.h>
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#include "bench.h"
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#ifndef BENCH_NR_SAMPLES
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#define BENCH_NR_SAMPLES 4096
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#endif
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#ifndef BENCH_NR_CPUS
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#define BENCH_NR_CPUS 256
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#endif
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typedef void (*bpf_bench_run_fn)(void *ctx);
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struct bpf_bench_timing {
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__u64 (*samples)[BENCH_NR_SAMPLES]; /* skel->bss->timing_samples */
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__u32 *idx; /* skel->bss->timing_idx */
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volatile __u32 *timing_enabled; /* &skel->bss->timing_enabled */
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volatile __u32 *batch_iters_bss; /* &skel->bss->batch_iters */
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__u32 batch_iters;
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__u32 target_samples;
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__u32 nr_cpus;
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int warmup_ticks;
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bool done;
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bool machine_readable;
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};
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#define BENCH_TIMING_INIT(t, skel, iters) do { \
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(t)->samples = (skel)->bss->timing_samples; \
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(t)->idx = (skel)->bss->timing_idx; \
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(t)->timing_enabled = &(skel)->bss->timing_enabled; \
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(t)->batch_iters_bss = &(skel)->bss->batch_iters; \
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(t)->batch_iters = (iters); \
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(t)->target_samples = 200; \
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(t)->nr_cpus = env.nr_cpus; \
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(t)->warmup_ticks = 0; \
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(t)->done = false; \
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(t)->machine_readable = false; \
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} while (0)
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void bpf_bench_timing_measure(struct bpf_bench_timing *t, struct bench_res *res);
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void bpf_bench_timing_report(struct bpf_bench_timing *t, const char *name, const char *desc);
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void bpf_bench_calibrate(struct bpf_bench_timing *t, bpf_bench_run_fn run_fn, void *ctx);
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#endif /* __BENCH_BPF_TIMING_H__ */
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