Subject: Re: ktr from freebsd
To: Andrey Petrov <petrov@NetBSD.org>
From: Rafal Boni <rafal@pobox.com>
List: tech-kern
Date: 04/23/2004 10:29:20
In message <20040422083606.GA16676@NetBSD.org>, you write: 

-> I needed low-level memory buffer tracing and I took freebsd's kern_ktr.c
-> for that. I stripped 'bells and whistls' like sysctl control and saving in
-> file,  because I don't think they are really needed and it would take more
-> time for porting. Main reason was replace sparc64 traptrace with something
-> more generic and flexible, uvm_history seems closest by functionality but 
-> too tied to uvm and somewhat too heavy for .S codes. So I ended up with
-> freebsd's kern_ktr and that's light-weight, simple and convinient interface.

This does look useful insofar as it's a general, light-weight tracing
facility... I also didn't know about uvmhist before (well, I did, but
also assumed it was uvm-specific) and so have probably implemented one-
off tracing solutions a couple of times now for tracking down things
like time-sensitive network driver bugs, etc.

IMHO, Documentation is key, I think, becuase if it's not documented, we
will likely have the same problem as I did with uvmhist stuff... people
will either be unaware of it or won't know how/why to use it and will keep
on inventing new wheels for this...

Thanks,
--rafal

----
Rafal Boni                                                     rafal@pobox.com
  We are all worms.  But I do believe I am a glowworm.  -- Winston Churchill