Subject: Re: [PATCH] perf tools: Add arm64 version of get_cpuid()

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Wed, 12 Feb 2020 10:40:24 -0300

Em Tue, Jan 07, 2020 at 09:13:43AM +0000, John Garry escreveu:
> On 13/12/2019 13:54, John Garry wrote:
> 
> Hi Arnaldo,
> 
> Do we need some reviews on this? Or was it missed/still catching up?

Got lost in the holidays, devconf.cz, vacations, sorry, picking it up
now, together with a Tested-by by Shaokun Zhang, some issues with the
formatting of the patch:

- Avoid starting lines with '#' as those will vanish when I use 'git am'

- Separate the commit log message from the diff using a '---' at the
  begining of the line, otherwise 'git am' fails

I fixed those up now, will test with my build containers, thanks.

- Arnaldo
 
> Cheers,
> John
> 
> > Add an arm64 version of get_cpuid(), which is used for various annotation
> > and headers - for example, I now get the CPUID in "perf report --header",
> > as shown in this snippet:
> > 
> > # hostname : ubuntu
> > # os release : 5.5.0-rc1-dirty
> > # perf version : 5.5.rc1.gbf8a13dc9851
> > # arch : aarch64
> > # nrcpus online : 96
> > # nrcpus avail : 96
> > # cpuid : 0x00000000480fd010
> > 
> > Since much of the code to read the MIDR is already in get_cpuid_str(),
> > factor out this code.
> > 
> > Signed-off-by: John Garry <[email-masked]>
> > 
> > diff --git a/tools/perf/arch/arm64/util/header.c b/tools/perf/arch/arm64/util/header.c
> > index a32e4b72a98f..d730666ab95d 100644
> > --- a/tools/perf/arch/arm64/util/header.c
> > +++ b/tools/perf/arch/arm64/util/header.c
> > @@ -1,8 +1,10 @@
> >   #include <stdio.h>
> >   #include <stdlib.h>
> >   #include <perf/cpumap.h>
> > +#include <util/cpumap.h>
> >   #include <internal/cpumap.h>
> >   #include <api/fs/fs.h>
> > +#include <errno.h>
> >   #include "debug.h"
> >   #include "header.h"
> > @@ -12,26 +14,21 @@
> >   #define MIDR_VARIANT_SHIFT      20
> >   #define MIDR_VARIANT_MASK       (0xf << MIDR_VARIANT_SHIFT)
> > -char *get_cpuid_str(struct perf_pmu *pmu)
> > +static int _get_cpuid(char *buf, size_t sz, struct perf_cpu_map *cpus)
> >   {
> > -	char *buf = NULL;
> > -	char path[PATH_MAX];
> >   	const char *sysfs = sysfs__mountpoint();
> > -	int cpu;
> >   	u64 midr = 0;
> > -	struct perf_cpu_map *cpus;
> > -	FILE *file;
> > +	int cpu;
> > -	if (!sysfs || !pmu || !pmu->cpus)
> > -		return NULL;
> > +	if (!sysfs || sz < MIDR_SIZE)
> > +		return EINVAL;
> > -	buf = malloc(MIDR_SIZE);
> > -	if (!buf)
> > -		return NULL;
> > +	cpus = perf_cpu_map__get(cpus);
> > -	/* read midr from list of cpus mapped to this pmu */
> > -	cpus = perf_cpu_map__get(pmu->cpus);
> >   	for (cpu = 0; cpu < perf_cpu_map__nr(cpus); cpu++) {
> > +		char path[PATH_MAX];
> > +		FILE *file;
> > +
> >   		scnprintf(path, PATH_MAX, "%s/devices/system/cpu/cpu%d"MIDR,
> >   				sysfs, cpus->map[cpu]);
> > @@ -57,12 +54,48 @@ char *get_cpuid_str(struct perf_pmu *pmu)
> >   		break;
> >   	}
> > -	if (!midr) {
> > +	perf_cpu_map__put(cpus);
> > +
> > +	if (!midr)
> > +		return EINVAL;
> > +
> > +	return 0;
> > +}
> > +
> > +int get_cpuid(char *buf, size_t sz)
> > +{
> > +	struct perf_cpu_map *cpus = perf_cpu_map__new(NULL);
> > +	int ret;
> > +
> > +	if (!cpus)
> > +		return EINVAL;
> > +
> > +	ret = _get_cpuid(buf, sz, cpus);
> > +
> > +	perf_cpu_map__put(cpus);
> > +
> > +	return ret;
> > +}
> > +
> > +char *get_cpuid_str(struct perf_pmu *pmu)
> > +{
> > +	char *buf = NULL;
> > +	int res;
> > +
> > +	if (!pmu || !pmu->cpus)
> > +		return NULL;
> > +
> > +	buf = malloc(MIDR_SIZE);
> > +	if (!buf)
> > +		return NULL;
> > +
> > +	/* read midr from list of cpus mapped to this pmu */
> > +	res = _get_cpuid(buf, MIDR_SIZE, pmu->cpus);
> > +	if (res) {
> >   		pr_err("failed to get cpuid string for PMU %s\n", pmu->name);
> >   		free(buf);
> >   		buf = NULL;
> >   	}
> > -	perf_cpu_map__put(cpus);
> >   	return buf;
> >   }
> > 
> 

-- 

- Arnaldo

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