|From:||Ingo Molnar <mingo-AT-elte.hu>|
|To:||Thomas Gleixner <tglx-AT-linutronix.de>|
|Subject:||Re: [RFD] Future tracing/instrumentation directions|
|Date:||Thu, 20 May 2010 13:42:18 +0200|
|Cc:||Frederic Weisbecker <fweisbec-AT-gmail.com>, Steven Rostedt <rostedt-AT-goodmis.org>, LKML <linux-kernel-AT-vger.kernel.org>, Linus Torvalds <torvalds-AT-linux-foundation.org>, Andrew Morton <akpm-AT-linux-foundation.org>, Peter Zijlstra <peterz-AT-infradead.org>, Christoph Hellwig <hch-AT-lst.de>, Mathieu Desnoyers <mathieu.desnoyers-AT-efficios.com>, Li Zefan <lizf-AT-cn.fujitsu.com>, Lai Jiangshan <laijs-AT-cn.fujitsu.com>, Johannes Berg <johannes.berg-AT-intel.com>, Masami Hiramatsu <masami.hiramatsu.pt-AT-hitachi.com>, Arnaldo Carvalho de Melo <acme-AT-infradead.org>, Tom Zanussi <tzanussi-AT-gmail.com>, KOSAKI Motohiro <kosaki.motohiro-AT-jp.fujitsu.com>, Andi Kleen <andi-AT-firstfloor.org>, Masami Hiramatsu <mhiramat-AT-redhat.com>, Lin Ming <ming.m.lin-AT-intel.com>, Cyrill Gorcunov <gorcunov-AT-gmail.com>, Mike Galbraith <efault-AT-gmx.de>, Paul Mackerras <paulus-AT-samba.org>, Hitoshi Mitake <mitake-AT-dcl.info.waseda|
* Thomas Gleixner <email@example.com> wrote: > On Thu, 20 May 2010, Frederic Weisbecker wrote: > > On Thu, May 20, 2010 at 11:31:31AM +0200, Ingo Molnar wrote: > > > - [ While it's still a long way off, if this trend continues > > > we eventually might even be able to get rid of the > > > /debug/tracing/ temporary debug API and get rid of > > > the ugly in-kernel pretty-printing bits. This is > > > good: it may make Andrew very happy for a change ;-) > > > > > > The main detail here to be careful of is that lots of > > > people are fond of the simplicity of the > > > /debug/tracing/ debug UI, so when we replace it we > > > want to do it by keeping that simple workflow (or > > > best by making it even simpler). I have a few ideas > > > how to do this. > > > > How? We can emulate the /debug/tracing result with something > > like perf trace, still that won't replace the immediate > > availability of the result of any trace, which makes it > > valuable for any simplest workflows. > > I'm a bit torn about this. I really like the availability of the ascii > interface, but if we can come up with a very basic trace binary tool > which can be built for deep embedded w/o requiring the world and some > more libs to be available, then I might give up my resistance. Ideally > it should be done so it can be easily integrated into busybox. > > I don't care whether I do > > echo 1 >/debug/..../XXX/enable > cat /debug/tracing/trace > > or > > perfmini trace enable XXX > perfmini trace dump My suggestion for that flow is even shorter: trace --enable XXX trace Plus: trace --list trace --enable trace --disable > as long as the tool is built in a way that it does not > need updates when we add trace points or other > functionality to the kernel. Yeah, most definitely. The sysfs event_source class will ensure that whatever (new) events are available propagate through the tool and are available to it. Thanks, Ingo
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