* [PATCH] perf: riscv: skip empty batches in counter start
@ 2025-08-04 2:51 Yunhui Cui
2025-08-04 4:54 ` Anup Patel
0 siblings, 1 reply; 2+ messages in thread
From: Yunhui Cui @ 2025-08-04 2:51 UTC (permalink / raw)
To: atish.patra, anup, will, mark.rutland, paul.walmsley, palmer, aou,
alex, linux-riscv, linux-arm-kernel, linux-perf-users,
linux-kernel
Cc: Yunhui Cui
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>
---
drivers/perf/riscv_pmu_sbi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 698de8ddf895b..3977f7488e4ef 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -877,8 +877,10 @@ static inline void pmu_sbi_start_ovf_ctrs_sbi(struct cpu_hw_events *cpu_hw_evt,
for (i = 0; i < BITS_TO_LONGS(RISCV_MAX_COUNTERS); i++) {
ctr_start_mask = cpu_hw_evt->used_hw_ctrs[i] & ~ctr_ovf_mask;
/* Start all the counters that did not overflow in a single shot */
- sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, i * BITS_PER_LONG, ctr_start_mask,
- 0, 0, 0, 0);
+ if (ctr_start_mask) {
+ sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, i * BITS_PER_LONG,
+ ctr_start_mask, 0, 0, 0, 0);
+ }
}
/* Reinitialize and start all the counter that overflowed */
--
2.39.5
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] perf: riscv: skip empty batches in counter start
2025-08-04 2:51 [PATCH] perf: riscv: skip empty batches in counter start Yunhui Cui
@ 2025-08-04 4:54 ` Anup Patel
0 siblings, 0 replies; 2+ messages in thread
From: Anup Patel @ 2025-08-04 4:54 UTC (permalink / raw)
To: Yunhui Cui
Cc: atish.patra, will, mark.rutland, paul.walmsley, palmer, aou, alex,
linux-riscv, linux-arm-kernel, linux-perf-users, linux-kernel
On Mon, Aug 4, 2025 at 8:21 AM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
>
> 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>
LGTM.
Reviewed-by: Anup Patel <anup@brainfault.org>
Regards,
Anup
> ---
> drivers/perf/riscv_pmu_sbi.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> index 698de8ddf895b..3977f7488e4ef 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c
> @@ -877,8 +877,10 @@ static inline void pmu_sbi_start_ovf_ctrs_sbi(struct cpu_hw_events *cpu_hw_evt,
> for (i = 0; i < BITS_TO_LONGS(RISCV_MAX_COUNTERS); i++) {
> ctr_start_mask = cpu_hw_evt->used_hw_ctrs[i] & ~ctr_ovf_mask;
> /* Start all the counters that did not overflow in a single shot */
> - sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, i * BITS_PER_LONG, ctr_start_mask,
> - 0, 0, 0, 0);
> + if (ctr_start_mask) {
> + sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, i * BITS_PER_LONG,
> + ctr_start_mask, 0, 0, 0, 0);
> + }
> }
>
> /* Reinitialize and start all the counter that overflowed */
> --
> 2.39.5
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2025-08-04 4:57 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-08-04 2:51 [PATCH] perf: riscv: skip empty batches in counter start Yunhui Cui
2025-08-04 4:54 ` Anup Patel
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).