From: Peter Zijlstra <peterz@infradead.org>
To: Jason Baron <jbaron@redhat.com>
Cc: hpa@zytor.com, rostedt@goodmis.org, mingo@elte.hu,
mathieu.desnoyers@polymtl.ca, tglx@linutronix.de,
andi@firstfloor.org, roland@redhat.com, rth@redhat.com,
masami.hiramatsu.pt@hitachi.com, fweisbec@gmail.com,
avi@redhat.com, davem@davemloft.net, sam@ravnborg.org,
ddaney@caviumnetworks.com, michael@ellerman.id.au,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH/RFC 1/2] jump label: make enable/disable o(1)
Date: Thu, 16 Dec 2010 20:33:51 +0100 [thread overview]
Message-ID: <1292528031.2708.77.camel@laptop> (raw)
In-Reply-To: <20101216192303.GB2856@redhat.com>
On Thu, 2010-12-16 at 14:23 -0500, Jason Baron wrote:
>
> For the jump label disabled case, perf is using atomic_inc/dec and atomic_read
> to check if enabled. While other consumers (tracepoints) are just using an
> 'int'. I didn't want hurt the jump label disabled case for tracepoints.
> If we can agree to use atomic ops for tracepoints, or drop atomics from
> perf, that would simplify things.
I had a quick look at the tracepoint stuff but got lost, but surely it
has a reference count somewhere as well, it needs to know when the last
probe goes away.. or does it check if the list is empty?
Anyway, tracepoint enable/disable isn't a real fast-path, surely it
could suffer an atomic op?
next prev parent reply other threads:[~2010-12-16 19:34 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-16 18:25 [PATCH/RFC 0/2] jump label: simplify API Jason Baron
2010-12-16 18:25 ` [PATCH/RFC 1/2] jump label: make enable/disable o(1) Jason Baron
2010-12-16 19:10 ` Peter Zijlstra
2010-12-16 19:23 ` Jason Baron
2010-12-16 19:33 ` Peter Zijlstra [this message]
2010-12-16 19:36 ` Jason Baron
2010-12-16 19:41 ` Peter Zijlstra
2010-12-16 19:48 ` Jason Baron
2010-12-16 20:09 ` Steven Rostedt
2010-12-16 20:36 ` Mathieu Desnoyers
2010-12-16 20:43 ` Peter Zijlstra
2010-12-16 20:50 ` Mathieu Desnoyers
2010-12-16 20:56 ` Peter Zijlstra
2010-12-17 20:07 ` Jason Baron
2010-12-17 20:51 ` David Daney
2010-12-17 21:12 ` Steven Rostedt
2010-12-17 21:32 ` Jason Baron
2010-12-16 20:45 ` Mathieu Desnoyers
2010-12-16 18:25 ` [PATCH/RFC 2/2] jump label: introduce unlikely_switch() Jason Baron
2010-12-16 19:22 ` [PATCH/RFC 0/2] jump label: simplify API Mathieu Desnoyers
2010-12-16 20:18 ` Steven Rostedt
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