From: Peter Zijlstra <peterz@infradead.org>
To: Feng Tang <feng.tang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Arjan van de Ven <arjan@linux.intel.com>,
Jonathan Corbet <corbet@lwn.net>, Ingo Molnar <mingo@kernel.org>,
Eric W Biederman <ebiederm@xmission.com>,
Dmitry Vyukov <dvyukov@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Andy Lutomirski <luto@kernel.org>,
Ying Huang <ying.huang@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/3] latencytop lock usage improvement
Date: Tue, 30 Apr 2019 11:10:33 +0200 [thread overview]
Message-ID: <20190430091033.GN2623@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190430083505.n5mozwybbnwydo3z@shbuild888>
On Tue, Apr 30, 2019 at 04:35:05PM +0800, Feng Tang wrote:
> Hi Peter,
>
> On Tue, Apr 30, 2019 at 10:09:10AM +0200, Peter Zijlstra wrote:
> > On Mon, Apr 29, 2019 at 04:03:28PM +0800, Feng Tang wrote:
> > > Hi All,
> > >
> > > latencytop is a very nice tool for tracing system latency hotspots, and
> > > we heavily use it in our LKP test suites.
> >
> > What data does latency-top give that perf cannot give you? Ideally we'd
> > remove latencytop entirely.
>
> Thanks for the review. In 0day/LKP test service, we have many tools for
> monitoring and analyzing the test results, perf is the most important
> one, which has the most parts in our auto-generated comparing results.
> For example to identify spinlock contentions and system hotspots.
>
> latencytop is another tool we used to find why systems go idle, like why
> workload chose to sleep or waiting for something.
You're not answering the question; why can't you use perf for that? ISTR
we explicitly added support for things like that.
next prev parent reply other threads:[~2019-04-30 9:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-29 8:03 [RFC PATCH 0/3] latencytop lock usage improvement Feng Tang
2019-04-29 8:03 ` [RFC PATCH 1/3] kernel/sysctl: add description for "latencytop" Feng Tang
2019-04-29 8:03 ` [RFC PATCH 2/3] latencytop: split latency_lock to global lock and per task lock Feng Tang
2019-04-29 8:03 ` [RFC PATCH 3/3] latencytop: add a lazy mode for updating global latency data Feng Tang
2019-04-30 8:09 ` [RFC PATCH 0/3] latencytop lock usage improvement Peter Zijlstra
2019-04-30 8:35 ` Feng Tang
2019-04-30 9:10 ` Peter Zijlstra [this message]
2019-04-30 9:22 ` Feng Tang
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