Article on Sun's DTrace

[Eitarou Kamo]

Hi Dan,

Daniel Ellard wrote:

>In a nutshell, here is what DTrace is about:
>
>- It has no impact on the system when it is not used.  So you can
>	leave it in all the time, instead of having a debug kernel and
>	a production kernel.
>
>	[I don't know how they achieve the "no impact" but they claim
>	that they really mean "no", not just "negligible".]
>  
>
<snip>
</snip>

Thanks good comment. This is the one everyone, of course me too,
wants to know. I wanted to get brief instruction.


>So, you could think of it as "a million debugging printf's magically
>inserted into the kernel for you" along with a tool to analyze the
>output, but it's really much more sophisticated than that.
>
>It looks very nice.  I wish I'd had it during my forays into the
>FreeBSD kernel.  Is it hopelessly solaris-specific?  Well, I was at
>the presentation that Bryan Cantrill gave at USENIX, where he was
>asked about the possibility of porting DTrace to linux.  His response
>was something like "well, we're really trying to encourage people to
>use the *best* possible operating system, so no." (Of course, one
>might argue that this means that a FreeBSD port is imminent, but I
>don't think that's what he meant.)
>
>-Dan
>
>  
>
FreeBSD has good features such as jail, chroot e.t.c. which can controll
process or resources in parallel. So you need not port DTrace entirely.
You can implement DTrace like one from scratch. Using legacy system
sometimes makes new system feature. I would rather expect new one than
porting. DTrace is one of example, I think. You may be able to fork new 
debug
process in parallel in the future. If I dare name it, It's "B(SD)Trace"? 
But it's up to
your effort. DTrace is a pioneer work. And for the people like me who 
bothers
to put the debug lines in kernel this must be powerful tool.

Eitarou

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