From: Peter Zijlstra <peterz@infradead.org>
To: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: ast@fb.com, lkml <linux-kernel@vger.kernel.org>,
acme@kernel.org, alexander.shishkin@linux.intel.com,
mingo@redhat.com, daniel@iogearbox.net, rostedt@goodmis.org,
Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
ebiederm@xmission.com, sargun@sargun.me,
Aravinda Prasad <aravinda@linux.vnet.ibm.com>,
brendan.d.gregg@gmail.com
Subject: Re: [PATCH v4 1/3] perf: add PERF_RECORD_NAMESPACES to include namespaces related info
Date: Wed, 21 Dec 2016 14:24:52 +0100 [thread overview]
Message-ID: <20161221132452.GT3124@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1702a267-0ce6-86da-7755-11a375e450e2@linux.vnet.ibm.com>
On Wed, Dec 21, 2016 at 06:39:01PM +0530, Hari Bathini wrote:
> Hi Peter,
> >I don't see how the tool can parse old records (with NAMESPACES_MAX ==
> >7) if you set its NAMESPACES_MAX to say 10.
> >
> >Then it will expect the link_info array to be 10 entries and either read
> >past the end of the record (if !sample_all) or try and interpret
> >sample_id as link_info records.
> >
>
> Right. There will be inconsistency with data the perf tool tries to read
> beyond
> what the kernel supports. IIUC, you mean, include nr_namespaces field in the
> record and warn the user if it doesn't match with the one perf-tool supports
> before proceeding..?
Yes, if you add a nr_namespaces field its always parsable. If an old
tool finds more namespace than it has 'names' for it can always display
the raw index number. If a new tool finds the array short, it will not
display the missing ones.
next prev parent reply other threads:[~2016-12-21 13:25 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-15 18:36 [PATCH v4 0/3] perf: add support for analyzing events for containers Hari Bathini
2016-12-15 18:37 ` [PATCH v4 1/3] perf: add PERF_RECORD_NAMESPACES to include namespaces related info Hari Bathini
2016-12-15 18:46 ` Peter Zijlstra
2016-12-16 6:27 ` Hari Bathini
2016-12-16 7:57 ` Peter Zijlstra
2016-12-16 18:21 ` Hari Bathini
2016-12-16 20:05 ` Peter Zijlstra
2016-12-21 13:09 ` Hari Bathini
2016-12-21 13:24 ` Peter Zijlstra [this message]
2016-12-21 15:56 ` Hari Bathini
2016-12-22 7:21 ` Eric W. Biederman
2016-12-22 7:53 ` Peter Zijlstra
2016-12-22 10:19 ` Eric W. Biederman
2016-12-22 13:24 ` Peter Zijlstra
2016-12-22 18:20 ` Eric W. Biederman
2016-12-15 18:37 ` [PATCH v4 2/3] perf tool: " Hari Bathini
2016-12-17 17:40 ` Jiri Olsa
2016-12-21 13:18 ` Hari Bathini
2016-12-15 18:37 ` [PATCH v4 3/3] perf tool: add cgroup identifier entry in perf report Hari Bathini
2016-12-29 1:41 ` [PATCH v4 0/3] perf: add support for analyzing events for containers Krister Johansen
2017-01-03 11:27 ` Hari Bathini
2017-01-04 9:04 ` Krister Johansen
2017-01-04 11:45 ` Hari Bathini
2017-01-11 11:16 ` Aravinda Prasad
2017-01-11 14:45 ` Eric W. Biederman
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