Re: [9fans] "Blocks" in C

[erik quanstrom <quanstro@quanstro.net>]

On Fri Sep 18 11:52:23 EDT 2009, drivers@0xabadba.be wrote:
>      Is there some method of lock profiling on plan9?  For example when I do work on freebsd and say remove a giant lock from the keyboard subsystem; I run the lock profiler before and after the change to see how long the system was sitting at the in kernel locks.
>      I am doing my thesis (undergrad) on these kind of topics and am interested in seeing how I may be of use.

use kprof.  or add your own instrumentation.

if you have very specific ideas about what needs
to be tracked, it's quite easy to implement.  that
would be an interesting project.  port/taslock.c
already tracks some lock statistics.  esp. lockstats.inglare
port/qlock has qlocks and rwlocks.

the tracking could use atomic increments.  as
it stands, i don't believe it is accurate because two
locks can be inglare at the same time.  thus inglar
would appear to be less than it should be.

- erik