From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
Li Zefan <lizf@cn.fujitsu.com>,
Prasad <prasad@linux.vnet.ibm.com>,
Alan Stern <stern@rowland.harvard.edu>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Jan Kiszka <jan.kiszka@web.de>, Jiri Slaby <jirislaby@gmail.com>,
Avi Kivity <avi@redhat.com>, Paul Mackerras <paulus@samba.org>,
Mike Galbraith <efault@gmx.de>,
Masami Hiramatsu <mhiramat@redhat.com>,
Paul Mundt <lethal@linux-sh.org>,
Arjan van de Ven <arjan@linux.intel.com>
Subject: Re: [PATCH 3/7 v6] perf/core: Add a callback to perf events
Date: Wed, 18 Nov 2009 10:31:09 +0100 [thread overview]
Message-ID: <1258536669.3918.99.camel@laptop> (raw)
In-Reply-To: <20091118001815.GA8187@nowhere>
On Wed, 2009-11-18 at 01:18 +0100, Frederic Weisbecker wrote:
> On Tue, Nov 17, 2009 at 12:28:53PM +0100, Peter Zijlstra wrote:
> > On Sun, 2009-11-08 at 16:28 +0100, Frederic Weisbecker wrote:
> > > A simple callback in a perf event can be used for multiple purposes.
> > > For example it is useful for triggered based events like hardware
> > > breakpoints that need a callback to dispatch a triggered breakpoint
> > > event.
> > >
> > > v2: Simplify a bit the callback attribution as suggested by Paul
> > > Mackerras
> >
> > Yuck! So we add an opaque callback without semantics nor usage.
>
>
> Yeah, this is intended for events that need to be able to trigger
> events to different channels. In the case of hw-breakpoints, it's
> either perf buffer, ptrace, etc...
>
> Should I add some comments about it?
At the very least.. describe its semantics and preferably rename the
thing.
Currently I've no clue what it does and why, your description above
about multiple channels does not at all help me understand how this
function pointer is used to make that happen.
next prev parent reply other threads:[~2009-11-18 9:31 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-08 15:28 [GIT PULL v6] hw-breakpoints: Rewrite on top of perf events v6 Frederic Weisbecker
2009-11-08 15:28 ` [PATCH 1/7 v6] perf/core: Provide a kernel-internal interface to get to performance counters Frederic Weisbecker
2009-11-08 15:28 ` [PATCH 2/7 v6] x86/hw-breakpoints: Actually flush thread breakpoints in flush_thread() Frederic Weisbecker
2009-11-08 15:28 ` [PATCH 3/7 v6] perf/core: Add a callback to perf events Frederic Weisbecker
2009-11-17 11:28 ` Peter Zijlstra
2009-11-18 0:18 ` Frederic Weisbecker
2009-11-18 9:31 ` Peter Zijlstra [this message]
2009-11-19 15:43 ` Frederic Weisbecker
2009-11-19 22:40 ` Peter Zijlstra
2009-11-08 15:28 ` [PATCH 4/7 v6] hw-breakpoint: Move asm-generic/hw_breakpoint.h to linux/hw_breakpoint.h Frederic Weisbecker
2009-11-08 15:28 ` [PATCH 5/7 v6] hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events Frederic Weisbecker
2009-11-08 17:24 ` Jan Kiszka
2009-11-12 14:32 ` Frederic Weisbecker
2009-11-11 13:02 ` K.Prasad
2009-11-12 4:25 ` K.Prasad
2009-11-17 1:36 ` Frederic Weisbecker
2009-11-17 1:31 ` Frederic Weisbecker
2009-11-17 11:30 ` Peter Zijlstra
2009-11-18 0:19 ` Frederic Weisbecker
2009-11-08 15:29 ` [PATCH 6/7 v6] hw-breakpoints: Arbitrate access to pmu following registers constraints Frederic Weisbecker
2009-11-08 15:29 ` [PATCH 7/7 v6] ksym_tracer: Remove KSYM_SELFTEST_ENTRY Frederic Weisbecker
2009-11-08 17:03 ` [GIT PULL v6] hw-breakpoints: Rewrite on top of perf events v6 Ingo Molnar
2009-11-24 9:44 ` K.Prasad
2009-11-24 10:13 ` Ingo Molnar
2009-11-24 13:21 ` K.Prasad
2009-11-26 5:59 ` Frederic Weisbecker
2009-11-27 19:07 ` K.Prasad
2009-12-01 6:43 ` Frederic Weisbecker
2009-11-26 5:47 ` Frederic Weisbecker
2009-11-26 9:01 ` Ingo Molnar
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