Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
perf: riscv: skip empty batches in counter start
Avoid unnecessary SBI calls when starting non-overflowed counters
in pmu_sbi_start_ovf_ctrs_sbi() by checking ctr_start_mask.
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20250804025110.11088-1-cuiyunhui@bytedance.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
authored by
Yunhui Cui
and committed by
Paul Walmsley
568a2fa1
f68cd7dd
+4
-2
+4
-2
drivers/perf/riscv_pmu_sbi.c
+4
-2
drivers/perf/riscv_pmu_sbi.c
···
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for (i = 0; i < BITS_TO_LONGS(RISCV_MAX_COUNTERS); i++) {
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ctr_start_mask = cpu_hw_evt->used_hw_ctrs[i] & ~ctr_ovf_mask;
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/* Start all the counters that did not overflow in a single shot */
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-
sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, i * BITS_PER_LONG, ctr_start_mask,
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-
0, 0, 0, 0);
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+
if (ctr_start_mask) {
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sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, i * BITS_PER_LONG,
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ctr_start_mask, 0, 0, 0, 0);
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}
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}
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/* Reinitialize and start all the counter that overflowed */