[gclist] Finalizers & Reference counting.
29 Aug 2002 11:05:10 -0400
On Wed, 2002-08-28 at 16:47, Reedy,Christopher L. (Chris) wrote:
> I'm sure you've seen the e-mail from Linus Torvalds on the GCC mailing
> list about reference counting versus garbage collection. For those who
> may not have seen it, here is a quote from the e-mail:
> > I strongly suspect that what makes gcc slow is that it has absolutely
> > horrible cache behaviour, a big VM footprint, and chases pointers in
> > that badly cached area all of the time.
Linus probably knows more about gcc than I do, but I think spending lots
of time in the kernel may have skewed his judgment. Visible performance
problems in the real world almost always stem from algorithms with poor
scaling characteristics (O(n^2) or worse, where n is actually growing
large). Not cache locality, not "hot spots" which need to be
hand-optimized, not anything like that.
Kernel programmers live in a world where cycle-counting optimizations
may make sense: every program on the system uses the kernel, so every
clock cycle you save in a common system call shaves off a little bit of
time for every program anyone runs. libc programmers live in the same
world. Everyone else should be looking at their algorithms and ignoring