lkml.org 
[lkml]   [2009]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH tracing/kprobes 4/7] tracing/kprobes: Add event profiling support
On Mon, Sep 14, 2009 at 12:54:24PM -0400, Masami Hiramatsu wrote:
>>> I'd like to have a dispatcher function and flags internally :)
>>
>>
>> You mean kprobes that could support multiple probes?
>> That would be a nice solution IMHO...
>
> Yeah, actually kprobes could support multiple probes on the
> same point. But kprobe structure has many extensions which
> kprobe-tracer doesn't need, e.g. post_handler/break_handler,
> opcode, arch sprcific instructions.
> Kretprobe consumes more memories for storing return points :(.
>
> Thus, if we know there are two functions to be called on the
> same probe point, I think it is better to have a dispatcher.
> (Especially, in this case, we can call fixed functions, so
> it's easier way.)
>


Yeah, you could union the post_handler with profile_handler
or something like that.

It depends if kprobes may need one day to support an undeterminate
number of probes.

Also, is the post_handler called at the same location than the normal
probe?
And is a post handler called even if there is no normal handler?


There might be some of such factors that would force you to handle a
lot of corner cases, things that you wouldn't need to worry about
if you just had to maintain a simple rcu list of probes to call.



\
 
 \ /
  Last update: 2009-09-14 20:59    [W:0.151 / U:0.700 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site