Re: [PATCH RFC 5/7] perf pmu: Support matching by sysid

From: Jiri Olsa <jolsa@redhat.com>
To: John Garry <john.garry@huawei.com>
Cc: mark.rutland@arm.com, ak@linux.intel.com, suzuki.poulose@arm.com,
	peterz@infradead.org, robin.murphy@arm.com, linuxarm@huawei.com,
	acme@kernel.org, linux-kernel@vger.kernel.org,
	zhangshaokun@hisilicon.com, alexander.shishkin@linux.intel.com,
	mingo@redhat.com, james.clark@arm.com, namhyung@kernel.org,
	will@kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH RFC 5/7] perf pmu: Support matching by sysid
Date: Tue, 11 Feb 2020 14:47:04 +0100	[thread overview]
Message-ID: <20200211134704.GB93194@krava> (raw)
In-Reply-To: <63799909-067b-e5f4-dcf1-9ba1ec145348@huawei.com>

On Mon, Feb 10, 2020 at 04:22:56PM +0000, John Garry wrote:
> Hi jirka,
> 
> > 
> > > +		fclose(file);
> > > +		pr_debug("gets failed for file %s\n", path);
> > > +		free(buf);
> > > +		return NULL;
> > > +	}
> > > +	fclose(file);
> > > +
> > > +	/* Remove any whitespace, this could be from ACPI HID */
> > > +	s = strlen(buf);
> > > +	for (i = 0; i < s; i++) {
> > > +		if (buf[i] == ' ') {
> > > +			buf[i] = 0;
> > > +			break;
> > > +		};
> > > +	}
> > > +
> > > +	return buf;
> > > +}
> > > +
> 
> I have another series to add kernel support for a system identifier sysfs
> entry, which I sent after this series:
> 
> https://lore.kernel.org/linux-acpi/1580210059-199540-1-git-send-email-john.garry@huawei.com/
> 
> It is different to what I am relying on here - it uses a kernel soc driver
> for firmware ACPI PPTT identifier. Progress is somewhat blocked at the
> moment however and I may have to use a different method:
> 
> https://lore.kernel.org/linux-acpi/20200128123415.GB36168@bogus/

I'll try to check ;-)

> 
> > > +static char *perf_pmu__getsysid(void)
> > > +{
> > > +	char *sysid;
> > > +	static bool printed;
> > > +
> > > +	sysid = getenv("PERF_SYSID");
> > > +	if (sysid)
> > > +		sysid = strdup(sysid);
> > > +
> > > +	if (!sysid)
> > > +		sysid = get_sysid_str();
> > > +	if (!sysid)
> > > +		return NULL;
> > > +
> > > +	if (!printed) {
> > > +		pr_debug("Using SYSID %s\n", sysid);
> > > +		printed = true;
> > > +	}
> > > +	return sysid;
> > > +}
> > 
> > this part is getting complicated and AFAIK we have no tests for it
> > 
> > if you could think of any tests that'd be great.. Perhaps we could
> > load 'our' json test files and check appropriate events/aliasses
> > via in pmu object.. or via parse_events interface.. those test aliases
> > would have to be part of perf, but we have tests compiled in anyway
> 
> Sorry, I don't fully follow.
> 
> Are you suggesting that we could load the specific JSONs tables for a system
> from the host filesystem?

I wish to see some test for all this.. I can only think about having
'test' json files compiled with perf and 'perf test' that looks them
up and checks that all is in the proper place

jirka

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