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Re: Discussion at Linux Foundation Japan Symposium
- From: "K.Prasad" <prasad at linux dot vnet dot ibm dot com>
- To: KOSAKI Motohiro <kosaki dot motohiro at jp dot fujitsu dot com>
- Cc: Jun Koi <junkoi2004 at gmail dot com>, Satoshi OSHIMA <satoshi dot oshima dot fk at hitachi dot com>, systemtap at sourceware dot org, mhiramat at redhat dot com, hisashi dot hashimoto dot wh at hitachi dot com, Yumiko SUGITA <yumiko dot sugita dot yf at hitachi dot com>
- Date: Thu, 18 Dec 2008 15:31:45 +0530
- Subject: Re: Discussion at Linux Foundation Japan Symposium
- References: <20081218181653.97C0.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20081218094539.GA4846@in.ibm.com> <20081218185148.94C3.KOSAKI.MOTOHIRO@jp.fujitsu.com>
- Reply-to: prasad at linux dot vnet dot ibm dot com
On Thu, Dec 18, 2008 at 06:57:57PM +0900, KOSAKI Motohiro wrote:
> > > Of cource, this approach indicate systemtap lost some feature.
> > > (e.g. above section don't have line number information and local
> > > variable name information)
> > >
> > > but it is still useful for average tracing user.
> > >
> > I'm not sure if the issue is discussed without being aware of the
> > dwarfless probing that's available in SystemTap since a while ago. More
> > details at: http://sourceware.org/systemtap/wiki/MakeDoWithoutDebugInfo
>
> Cool.
>
> but, I feel "must asmlinkage" is too strong restriction.
> Now, ftrace can trace any function by -pg compile option and
> self modification code.
>
> Can we do the same thing?
> I think ftrace approach have very few performance degression and
> we can apply production kernel.
>
investigate ftrace interface:
http://sources.redhat.com/bugzilla/show_bug.cgi?id=6594
Thanks,
K.Prasad