From: "Prakhya, Sai Praneeth" <sai.praneeth.prakhya@intel.com>
To: "Chatre, Reinette" <reinette.chatre@intel.com>,
"shuah@kernel.org" <shuah@kernel.org>,
"linux-kselftest@vger.kernel.org"
<linux-kselftest@vger.kernel.org>
Cc: "tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"bp@alien8.de" <bp@alien8.de>, "Luck, Tony" <tony.luck@intel.com>,
"babu.moger@amd.com" <babu.moger@amd.com>,
"james.morse@arm.com" <james.morse@arm.com>,
"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
"Yu, Fenghua" <fenghua.yu@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH V1 01/13] selftests/resctrl: Fix feature detection
Date: Mon, 9 Mar 2020 22:22:56 +0000 [thread overview]
Message-ID: <FFF73D592F13FD46B8700F0A279B802F57307F89@ORSMSX114.amr.corp.intel.com> (raw)
In-Reply-To: <a7407b0d-4e4d-d0cf-621c-769d218fdace@intel.com>
Hi Reinette,
> -----Original Message-----
> From: Reinette Chatre <reinette.chatre@intel.com>
> Sent: Monday, March 9, 2020 2:45 PM
> To: Prakhya, Sai Praneeth <sai.praneeth.prakhya@intel.com>;
> shuah@kernel.org; linux-kselftest@vger.kernel.org
> Cc: tglx@linutronix.de; mingo@redhat.com; bp@alien8.de; Luck, Tony
> <tony.luck@intel.com>; babu.moger@amd.com; james.morse@arm.com;
> Shankar, Ravi V <ravi.v.shankar@intel.com>; Yu, Fenghua
> <fenghua.yu@intel.com>; x86@kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH V1 01/13] selftests/resctrl: Fix feature detection
>
> Hi Sai,
>
> On 3/6/2020 7:40 PM, Sai Praneeth Prakhya wrote:
> > From: Reinette Chatre <reinette.chatre@intel.com>
> >
> > The intention of the resctrl selftests is to only run the tests
> > associated with the feature(s) supported by the platform. Through
> > parsing of the feature flags found in /proc/cpuinfo it is possible to
> > learn which features are supported by the plaform.
> >
> > There are currently two issues with the platform feature detection
> > that together result in tests always being run, whether the platform
> > supports a feature or not. First, the parsing of the the feature flags
> > loads the line containing the flags in a buffer that is too small (256
> > bytes) to always contain all flags. The consequence is that the flags
> > of the features being tested for may not be present in the buffer.
> > Second, the actual test for presence of a feature has an error in the
> > logic, negating the test for a particular feature flag instead of
> > testing for the presence of a particular feature flag.
> >
> > These two issues combined results in all tests being run on all
> > platforms, whether the feature is supported or not.
> >
> > Fix these issue by (1) increasing the buffer size being used to parse
> > the feature flags, and (2) change the logic to test for presence of
> > the feature being tested for.
> >
> > Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
> > Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
> > ---
> > tools/testing/selftests/resctrl/resctrlfs.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/testing/selftests/resctrl/resctrlfs.c
> > b/tools/testing/selftests/resctrl/resctrlfs.c
> > index 19c0ec4045a4..226dd7fdcfb1 100644
> > --- a/tools/testing/selftests/resctrl/resctrlfs.c
> > +++ b/tools/testing/selftests/resctrl/resctrlfs.c
> > @@ -596,11 +596,11 @@ bool check_resctrlfs_support(void)
> >
> > char *fgrep(FILE *inf, const char *str) {
> > - char line[256];
> > int slen = strlen(str);
> > + char line[2048];
> >
> > while (!feof(inf)) {
> > - if (!fgets(line, 256, inf))
> > + if (!fgets(line, 2048, inf))
> > break;
> > if (strncmp(line, str, slen))
> > continue;
> > @@ -631,7 +631,7 @@ bool validate_resctrl_feature_request(char
> *resctrl_val)
> > if (res) {
> > char *s = strchr(res, ':');
> >
> > - found = s && !strstr(s, resctrl_val);
> > + found = s && strstr(s, resctrl_val);
> > free(res);
> > }
> > fclose(inf);
> >
>
> Please note that this is only a partial fix. The current feature detection relies on
> the feature flags found in /proc/cpuinfo. Quirks and kernel boot parameters are
> not taken into account. This fix only addresses the parsing of feature flags. If a
> feature has been disabled via kernel boot parameter or quirk then the resctrl
> tests would still attempt to run the test for it.
That's a good point and makes sense to me. I think we could fix it in two ways
1. grep for strings in dmesg but that will still leave ambiguity in deciding b/w mbm and cqm because kernel prints "resctrl: L3 monitoring detected" for both the features
2. Check in "info" directory
a. For cat_l3, we could search for info/L3
b. For mba, we could search for info/MB
c. For cqm and mbm, we could search for specified string in info/L3_MON/mon_features
I think option 2 might be better because it can handle all cases, please let me know what you think.
Regards,
Sai
next prev parent reply other threads:[~2020-03-09 22:23 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-07 3:40 [PATCH V1 00/13] Miscellaneous fixes for resctrl selftests Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 01/13] selftests/resctrl: Fix feature detection Sai Praneeth Prakhya
2020-03-09 21:44 ` Reinette Chatre
2020-03-09 22:22 ` Prakhya, Sai Praneeth [this message]
2020-03-09 22:33 ` Reinette Chatre
2020-03-09 22:51 ` Prakhya, Sai Praneeth
2020-03-11 18:06 ` Reinette Chatre
2020-03-11 18:22 ` Sai Praneeth Prakhya
2020-03-11 18:45 ` Reinette Chatre
2020-03-11 18:54 ` Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 02/13] selftests/resctrl: Fix typo Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 03/13] selftests/resctrl: Fix typo in help text Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 04/13] selftests/resctrl: Ensure sibling CPU is not same as original CPU Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 05/13] selftests/resctrl: Fix missing options "-n" and "-p" Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 06/13] selftests/resctrl: Fix MBA/MBM results reporting format Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 07/13] selftests/resctrl: Don't use variable argument list for setup function Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 08/13] selftests/resctrl: Fix typos Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 09/13] selftests/resctrl: Modularize fill_buf for new CAT test case Sai Praneeth Prakhya
2020-03-10 21:59 ` Reinette Chatre
2020-03-11 1:04 ` Sai Praneeth Prakhya
[not found] ` <50cb755f-e112-5d71-11fa-a7cbc951d91e@intel.com>
2020-03-11 17:45 ` Sai Praneeth Prakhya
2020-03-11 18:10 ` Reinette Chatre
2020-03-11 18:14 ` Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 10/13] selftests/resctrl: Change Cache Allocation Technology (CAT) test Sai Praneeth Prakhya
2020-03-10 22:14 ` Reinette Chatre
2020-03-11 1:59 ` Sai Praneeth Prakhya
2020-03-11 17:03 ` Reinette Chatre
2020-03-11 19:14 ` Sai Praneeth Prakhya
2020-03-11 20:22 ` Reinette Chatre
2020-03-11 20:55 ` Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 11/13] selftests/resctrl: Change Cache Quality Monitoring (CQM) test Sai Praneeth Prakhya
2020-03-10 22:18 ` Reinette Chatre
2020-03-11 2:46 ` Sai Praneeth Prakhya
2020-03-11 17:19 ` Reinette Chatre
2020-03-11 17:33 ` Sai Praneeth Prakhya
2020-03-11 18:03 ` Reinette Chatre
2020-03-11 18:07 ` Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 12/13] selftests/resctrl: Dynamically select buffer size for CAT test Sai Praneeth Prakhya
2020-03-10 22:19 ` Reinette Chatre
2020-03-11 2:52 ` Sai Praneeth Prakhya
2020-03-07 3:40 ` [PATCH V1 13/13] selftests/resctrl: Cleanup fill_buff after changing " Sai Praneeth Prakhya
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