From: Peter Zijlstra <peterz@infradead.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>,
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>,
sargun@sargun.me, Aravinda Prasad <aravinda@linux.vnet.ibm.com>,
brendan.d.gregg@gmail.com, jolsa@redhat.com
Subject: Re: [PATCH v6 1/3] perf: add PERF_RECORD_NAMESPACES to include namespaces related info
Date: Thu, 16 Feb 2017 12:47:17 +0100 [thread overview]
Message-ID: <20170216114717.GY6500@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <87zihmtm1k.fsf@xmission.com>
On Fri, Feb 17, 2017 at 12:25:27AM +1300, Eric W. Biederman wrote:
> > +/*
> > + * The maximum size of the name of each namespace
> > + */
> > +#define NS_NAME_SIZE 8
> > +
> > +struct perf_ns_link_info {
> > + char name[NS_NAME_SIZE];
> > + __u64 dev;
> > + __u64 ino;
> > +};
>
> Ugh. I missed the name the first time around.
>
> That really looks like useless clutter. You already know the index so
> the name doesn't add any information, so unless I am missing something
> that name will just slow down the perf kernel implementation with
> useless work.
>
> The userspace reader can have the information just as reliably by
> looking at the index and indexing into a table.
>
> The set of namespaces changes slowly enough that this is not likely to
> be a problem in practice. Especially as perf is released with the
> kernel.
Right; Hari, please ditch that name thing.
next prev parent reply other threads:[~2017-02-16 11:47 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-08 8:31 [PATCH v6 0/3] perf: add support for analyzing events for containers Hari Bathini
2017-02-08 8:31 ` [PATCH v6 1/3] perf: add PERF_RECORD_NAMESPACES to include namespaces related info Hari Bathini
2017-02-16 10:28 ` Peter Zijlstra
2017-02-16 10:36 ` Peter Zijlstra
2017-02-20 4:11 ` Hari Bathini
2017-02-16 11:25 ` Eric W. Biederman
2017-02-16 11:47 ` Peter Zijlstra [this message]
2017-02-20 4:16 ` Hari Bathini
2017-02-08 8:31 ` [PATCH v6 2/3] perf tool: " Hari Bathini
2017-02-08 12:57 ` Jiri Olsa
2017-02-08 12:57 ` Jiri Olsa
2017-02-08 12:57 ` Jiri Olsa
2017-02-21 14:03 ` Hari Bathini
2017-02-08 8:32 ` [PATCH v6 3/3] perf tool: add cgroup identifier entry in perf report Hari Bathini
2017-02-16 6:20 ` [PATCH v6 0/3] perf: add support for analyzing events for containers Eric W. Biederman
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