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

  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>
---
 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(-)
  

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 */
  

On Fri, Jan 13, 2023 at 1:22 AM Jing Zhang <renyu.zj@linux.alibaba.com> wrote:
>
> 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>
> ---
>  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)

I'm not sure "find_same" is the best name here. I suspect it should be
"find_core_pmu" which would agree with is_arm_pmu_core. Unfortunately
"core" has become an overloaded term sometimes used interchangeably
with CPU, hyperthread or SMT thread, it was a model name for Intel and
it is used to distinguish a set of SMT threads running together from a
single one. Anyway, for consistency I think perf_pmu__find_core_pmu is
the most appropriate name (or pmu__find_core_pmu, I'm not sure why we
get the extra perf_ prefix sometimes, in general that indicates the
functionality is in libperf).

Aside from that, lgtm. Thanks,
Ian

>  {
>         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 */
> --
> 1.8.3.1
>
  

在 2023/1/15 上午6:15, Ian Rogers 写道:
> On Fri, Jan 13, 2023 at 1:22 AM Jing Zhang <renyu.zj@linux.alibaba.com> wrote:
>>
>> 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>
>> ---
>>  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)
> 
> I'm not sure "find_same" is the best name here. I suspect it should be
> "find_core_pmu" which would agree with is_arm_pmu_core. Unfortunately
> "core" has become an overloaded term sometimes used interchangeably
> with CPU, hyperthread or SMT thread, it was a model name for Intel and
> it is used to distinguish a set of SMT threads running together from a
> single one. Anyway, for consistency I think perf_pmu__find_core_pmu is
> the most appropriate name (or pmu__find_core_pmu, I'm not sure why we
> get the extra perf_ prefix sometimes, in general that indicates the
> functionality is in libperf).
> 

The reason for using "pmu_core__find_same" before is to indicate that we're
only dealing with homogeneous cores. And in the tools/perf/util/pmu.c file,
most of the static functions have "pmu_" prefix, maybe we can use
"pmu_find_same_core_pmu"? Ian, John, what do you think?

Thanks,
Jing

> Aside from that, lgtm. Thanks,
> Ian
> 
>>  {
>>         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 */
>> --
>> 1.8.3.1
>>
  

On Sun, Jan 15, 2023 at 6:58 PM Jing Zhang <renyu.zj@linux.alibaba.com> wrote:
>
> 在 2023/1/15 上午6:15, Ian Rogers 写道:
> > On Fri, Jan 13, 2023 at 1:22 AM Jing Zhang <renyu.zj@linux.alibaba.com> wrote:
> >>
> >> 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>
> >> ---
> >>  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)
> >
> > I'm not sure "find_same" is the best name here. I suspect it should be
> > "find_core_pmu" which would agree with is_arm_pmu_core. Unfortunately
> > "core" has become an overloaded term sometimes used interchangeably
> > with CPU, hyperthread or SMT thread, it was a model name for Intel and
> > it is used to distinguish a set of SMT threads running together from a
> > single one. Anyway, for consistency I think perf_pmu__find_core_pmu is
> > the most appropriate name (or pmu__find_core_pmu, I'm not sure why we
> > get the extra perf_ prefix sometimes, in general that indicates the
> > functionality is in libperf).
> >
>
> The reason for using "pmu_core__find_same" before is to indicate that we're
> only dealing with homogeneous cores. And in the tools/perf/util/pmu.c file,
> most of the static functions have "pmu_" prefix, maybe we can use
> "pmu_find_same_core_pmu"? Ian, John, what do you think?

I wouldn't necessarily worry about hybrid given #slots is currently
ARM specific. For hybrid we'd need to know the CPU for the metric. We
do have the list of CPUs (really hyper/SMT threads) that were
requested for the metric:
https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/tree/tools/perf/util/expr.h?h=perf/core#n9
We use it to compute the #core_wide literal. We need the value early
before events are created, hence the string format. You could search
pmus looking for a PMU that isn't uncore and has matching CPUs, but
AMD has multiple core/hardware PMUs (hence Ravi's most recent work)
and so I suspect we'd need to extend PMU to make this work. We've
solved a similar problem to this with the source_count metric
function, that returns a number of aliased events. We could do
something like:
slots(INST_RETIRED.MACRO_FUSED)
and then from the event get the PMU, from the PMU get the CPUs, from a
CPU get the slots. In that case it may just be cleaner to pass the PMU
name to the slots function, so:
slots(cpu_core) or slots(cpu_atom)
But the parser wouldn't understand that cpu_core or cpu_atom were PMU
names and would try to handle them as events or metric references.

Again, I think ignoring the hybrid case is fine in this case. Using
"same" in the function name to imply "not hybrid" I don't think works,
so I think something like pmu__find_core_pmu is best. You could have a
comment and also a:
assert(!perf_pmu__is_hybrid(pmu->name));
Ultimately I'd like to get rid of all notions of hybrid and just pair
events with a PMU. I recently cleaned this up in builtin-list.c.

Thanks,
Ian

> Thanks,
> Jing
>
> > Aside from that, lgtm. Thanks,
> > Ian
> >
> >>  {
> >>         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 */
> >> --
> >> 1.8.3.1
> >>
  

在 2023/1/16 下午1:59, Ian Rogers 写道:
> On Sun, Jan 15, 2023 at 6:58 PM Jing Zhang <renyu.zj@linux.alibaba.com> wrote:
>>
>> 在 2023/1/15 上午6:15, Ian Rogers 写道:
>>> On Fri, Jan 13, 2023 at 1:22 AM Jing Zhang <renyu.zj@linux.alibaba.com> wrote:
>>>>
>>>> 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>
>>>> ---
>>>>  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)
>>>
>>> I'm not sure "find_same" is the best name here. I suspect it should be
>>> "find_core_pmu" which would agree with is_arm_pmu_core. Unfortunately
>>> "core" has become an overloaded term sometimes used interchangeably
>>> with CPU, hyperthread or SMT thread, it was a model name for Intel and
>>> it is used to distinguish a set of SMT threads running together from a
>>> single one. Anyway, for consistency I think perf_pmu__find_core_pmu is
>>> the most appropriate name (or pmu__find_core_pmu, I'm not sure why we
>>> get the extra perf_ prefix sometimes, in general that indicates the
>>> functionality is in libperf).
>>>
>>
>> The reason for using "pmu_core__find_same" before is to indicate that we're
>> only dealing with homogeneous cores. And in the tools/perf/util/pmu.c file,
>> most of the static functions have "pmu_" prefix, maybe we can use
>> "pmu_find_same_core_pmu"? Ian, John, what do you think?
> 
> I wouldn't necessarily worry about hybrid given #slots is currently
> ARM specific. For hybrid we'd need to know the CPU for the metric. We
> do have the list of CPUs (really hyper/SMT threads) that were
> requested for the metric:
> https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/tree/tools/perf/util/expr.h?h=perf/core#n9
> We use it to compute the #core_wide literal. We need the value early
> before events are created, hence the string format. You could search
> pmus looking for a PMU that isn't uncore and has matching CPUs, but
> AMD has multiple core/hardware PMUs (hence Ravi's most recent work)
> and so I suspect we'd need to extend PMU to make this work. We've
> solved a similar problem to this with the source_count metric
> function, that returns a number of aliased events. We could do
> something like:
> slots(INST_RETIRED.MACRO_FUSED)
> and then from the event get the PMU, from the PMU get the CPUs, from a
> CPU get the slots. In that case it may just be cleaner to pass the PMU
> name to the slots function, so:
> slots(cpu_core) or slots(cpu_atom)
> But the parser wouldn't understand that cpu_core or cpu_atom were PMU
> names and would try to handle them as events or metric references.
> 
> Again, I think ignoring the hybrid case is fine in this case. Using
> "same" in the function name to imply "not hybrid" I don't think works,
> so I think something like pmu__find_core_pmu is best. You could have a
> comment and also a:
> assert(!perf_pmu__is_hybrid(pmu->name));
> Ultimately I'd like to get rid of all notions of hybrid and just pair
> events with a PMU. I recently cleaned this up in builtin-list.c.
> 

Ok, you are right, I follow your suggestion and use pmu__find_core_pmu.

I think “if (pmu->cpus->nr != cpu__max_cpu().cpu)” in the original code
and “assert(!perf_pmu__is_hybrid(pmu->name))” have the same effect, so
I will not change it.

> Thanks,
> Ian
> 
>> Thanks,
>> Jing
>>
>>> Aside from that, lgtm. Thanks,
>>> Ian
>>>
>>>>  {
>>>>         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 */
>>>> --
>>>> 1.8.3.1
>>>>