selftests/bpf: Filter timing outliers with IQR in batch-timing library

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System noise (timer interrupts, scheduling) can inflate the reported
stddev.  tcp-v4-syn showed stddev 37.86 ns without filtering vs
0.16 ns with filtering on the same run data.

Filter samples outside [Q1 - 1.5*IQR, Q3 + 1.5*IQR] before computing
statistics.  Scenarios with genuinely wide distributions have large IQR
so the fences stay wide and the filter has minimal effect.

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260520133338.3392667-4-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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Puranjay Mohan 2026-05-20 06:33:32 -07:00 • committed by Alexei Starovoitov

parent 12e896b979

commit abac8acb63

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tools/testing/selftests/bpf/benchs/bench_bpf_timing.c

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