Messages in this thread |  | | | Date | Mon, 16 Mar 2009 15:28:17 -0400 | | From | Mathieu Desnoyers <> | | Subject | Re: [Patch 2/2] tracepoints for softirq entry/exit - tracepoints |
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* Steven Rostedt (rostedt@goodmis.org) wrote: > > On Mon, 16 Mar 2009, Steven Rostedt wrote: > > > > > On Mon, 16 Mar 2009, Mathieu Desnoyers wrote: > > > > > > > > > > The softirq tracepoints are a good idea indeed (I have similar ones in > > > > > the LTTng tree). My main concern is about the fact that you output the > > > > > softirq name in plain text to the trace buffers. I would rather prefer > > > > > to save only the softirq (h-vec) into the trace and dump the mapping > > > > > (h-vec) to name only once, so we can save precious trace bytes. > > > > > > > > The TP_FMT is only used by those tracers that want to use it. Any tracer > > > > can still hook directly to the trace point and do what every they want. > > > > > > > > -- Steve > > > > > > > > > > By doing so, you are removing the ability to use the TP_FMT information > > > to perform high-speed system-wide tracing. I thought the goal was to > > > create a unified buffering, but sadly I don't see the high-speed > > > requirements being part of that plan. > > > > TP_FMT has nothing to do with the unified buffering. The unified buffer > > does not even know about it. But if you want high-speed event tracing, > > that is what the TRACE_EVENT was created for. > > Here's an example: > > The "event tracing" uses the format field to show those events for the > hook in the sched switching, and wake ups. > > The wake up tracer on the other hand, does not care about the format, it > only cares about having a hook where a a task is woken up, and where it > gets scheduled in, and perhaps events in between. But it uses its own > formatting to do the output. > > -- Steve >
If I understand you correctly, the format string is only useful to the text-output tracer ? Why can't it be used to identify both text and binary events ?
And remember that from my perspective, information is only useful if available for system-wide tracing. Specialized tracers come as a subset of system-wide tracing anyway when the latter is implemented with the proper hooks.
Mathieu
-- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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