valgrind stuff

Marc Lehmann schmorp at schmorp.de
Thu Apr 10 01:43:24 CEST 2008


On Wed, Apr 09, 2008 at 06:15:27PM -0500, Brandon Black <blblack at gmail.com> wrote:
> Regardless, if poll() returns zero there's no point in examining revents 
> anyways right?

The extra test might slow you down when you need it most, when you are in
a tight loop handling I/O events, especially when it is hard to predict.

> That makes the whole issue moot. 

Well, I'd rather have bugs fixed, especially in tools like valgrind that I
use myself.

You might not care about the quality of the software you use, but I do. And
when I use valgrind, I expect useful and good results, not false positives.

Think about how much time you and I already have potentially wasted on this
valgrund bug. This wouldn't have been neccessary if valgrind were fixed.

And yes, you might not care, but I am happy when _other_ people who find
out about these issues get the real bug fixed, so _I_ do not have to waste
time investigating them. With your attitude, everybody would just slap
workarounds around kernel bugs and everybody would have to reinvent those
workarounds again and again.

I have different standards.

> If anything you gain some performance by not scanning the poll_fd's in
> the case of a timeout with no events occuring.

Micro-optimisations like these often don't have the intended effect,
though, you have to look at the larger picture.

Besides, the point is not avoiding code changes to libev - if you had
looked, you had seen that I already added a workaround, despite having no
indicationg of this beign a real problem.

The point is a) fixing a real bug in a tool people rely on (valgrind) and
b) helping others by epxloring and fixing the issue, instead of blindly
applying some kludgy that might not even be necessary and letting others
stumble upon the same problems.

And yes, you might not care, but that doesn't mean it's good if other
people care for the quality of their and other's software. Free software
lives from people who *do* care about bugs, otherwise free software
wouldn't have the high quality that is (usually) has.

-- 
                The choice of a       Deliantra, the free code+content MORPG
      -----==-     _GNU_              http://www.deliantra.net
      ----==-- _       generation
      ---==---(_)__  __ ____  __      Marc Lehmann
      --==---/ / _ \/ // /\ \/ /      pcg at goof.com
      -=====/_/_//_/\_,_/ /_/\_\



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