Re: [PATCH v7 1/9] perf pmu: Add #slots literal support for arm64

[Jing Zhang <renyu.zj@linux.alibaba.com>]

在 2023/1/13 下午5:22, Jing Zhang 写道:
> The slots in each architecture may be different, so add #slots literal
> to obtain the slots of different architectures, and the #slots can be
> applied in the metric. Currently, The #slots just support for arm64,
> and other architectures will return NAN.
> 
> On arm64, the value of slots is from the register PMMIR_EL1.SLOT, which
> I can read in /sys/bus/event_source/device/armv8_pmuv3_*/caps/slots.
> PMMIR_EL1.SLOT might read as zero if the PMU version is lower than
> ID_AA64DFR0_EL1_PMUVer_V3P4 or the STALL_SLOT event is not implemented.
> 
> Signed-off-by: Jing Zhang <renyu.zj@linux.alibaba.com>
> ---

Hi Ian,

I have made significant changes compared to the previous two versions, so
I have not picked up your acked-by tags in this version. I look forward to
your review and give me a tag again. Thank you very much.

Thanks,
Jing


>  tools/perf/arch/arm64/util/pmu.c | 34 ++++++++++++++++++++++++++++++++--
>  tools/perf/util/expr.c           |  5 +++++
>  tools/perf/util/pmu.c            |  6 ++++++
>  tools/perf/util/pmu.h            |  1 +
>  4 files changed, 44 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/arch/arm64/util/pmu.c b/tools/perf/arch/arm64/util/pmu.c
> index 477e513..5f8667b 100644
> --- a/tools/perf/arch/arm64/util/pmu.c
> +++ b/tools/perf/arch/arm64/util/pmu.c
> @@ -3,8 +3,9 @@
>  #include <internal/cpumap.h>
>  #include "../../../util/cpumap.h"
>  #include "../../../util/pmu.h"
> +#include <api/fs/fs.h>
>  
> -const struct pmu_events_table *pmu_events_table__find(void)
> +static struct perf_pmu *pmu_core__find_same(void)
>  {
>  	struct perf_pmu *pmu = NULL;
>  
> @@ -19,8 +20,37 @@ const struct pmu_events_table *pmu_events_table__find(void)
>  		if (pmu->cpus->nr != cpu__max_cpu().cpu)
>  			return NULL;
>  
> -		return perf_pmu__find_table(pmu);
> +		return pmu;
>  	}
>  
>  	return NULL;
>  }
> +
> +const struct pmu_events_table *pmu_events_table__find(void)
> +{
> +	struct perf_pmu *pmu = pmu_core__find_same();
> +
> +	if (pmu)
> +		return perf_pmu__find_table(pmu);
> +
> +	return NULL;
> +}
> +
> +double perf_pmu__cpu_slots_per_cycle(void)
> +{
> +	char path[PATH_MAX];
> +	unsigned long long slots = 0;
> +	struct perf_pmu *pmu = pmu_core__find_same();
> +
> +	if (pmu) {
> +		scnprintf(path, PATH_MAX,
> +			EVENT_SOURCE_DEVICE_PATH "%s/caps/slots", pmu->name);
> +		/*
> +		 * The value of slots is not greater than 32 bits, but sysfs__read_int
> +		 * can't read value with 0x prefix, so use sysfs__read_ull instead.
> +		 */
> +		sysfs__read_ull(path, &slots);
> +	}
> +
> +	return (double)slots;
> +}
> diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
> index 00dcde3..9d3076a 100644
> --- a/tools/perf/util/expr.c
> +++ b/tools/perf/util/expr.c
> @@ -19,6 +19,7 @@
>  #include <linux/zalloc.h>
>  #include <ctype.h>
>  #include <math.h>
> +#include "pmu.h"
>  
>  #ifdef PARSER_DEBUG
>  extern int expr_debug;
> @@ -448,6 +449,10 @@ double expr__get_literal(const char *literal, const struct expr_scanner_ctx *ctx
>  		result = topology->core_cpus_lists;
>  		goto out;
>  	}
> +	if (!strcmp("#slots", literal)) {
> +		result = perf_pmu__cpu_slots_per_cycle() ?: NAN;
> +		goto out;
> +	}
>  
>  	pr_err("Unrecognized literal '%s'", literal);
>  out:
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 2bdeb89..cbb4fbf 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -19,6 +19,7 @@
>  #include <regex.h>
>  #include <perf/cpumap.h>
>  #include <fnmatch.h>
> +#include <math.h>
>  #include "debug.h"
>  #include "evsel.h"
>  #include "pmu.h"
> @@ -1993,3 +1994,8 @@ int perf_pmu__cpus_match(struct perf_pmu *pmu, struct perf_cpu_map *cpus,
>  	*ucpus_ptr = unmatched_cpus;
>  	return 0;
>  }
> +
> +double __weak perf_pmu__cpu_slots_per_cycle(void)
> +{
> +	return NAN;
> +}
> diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
> index 69ca000..fd414ba 100644
> --- a/tools/perf/util/pmu.h
> +++ b/tools/perf/util/pmu.h
> @@ -259,4 +259,5 @@ int perf_pmu__cpus_match(struct perf_pmu *pmu, struct perf_cpu_map *cpus,
>  
>  char *pmu_find_real_name(const char *name);
>  char *pmu_find_alias_name(const char *name);
> +double perf_pmu__cpu_slots_per_cycle(void);
>  #endif /* __PMU_H */