21 Feb
2012
21 Feb
'12
3:47 p.m.
On 02/21/2012 02:00 PM, Toby Thain wrote:
I've *only* ever seen a superlinear speedup on parallel builds. Are your
Makefiles ok?
Yes, I know how to write correct Makefiles.
I did not mean to suggest otherwise. I disagree with some of your
viewpoints, but I know that you know your stuff.
Not an
embedded system, but at work we have access to a multicore SPARC
system (Sun, I don't recall the model since it's actually stashed away
in a
data center) with 8 cores. Doing a parallel make (it helps to have a
properly written makefile; I went to the trouble to do so for the part
I'm
responsible for) only takes 1/10th the time of a non-parallel make.
Impressive. I've yet to see a *super*linear speedup for parallel make,
myself.
--Toby (uses 8 core at work) By superlinear I mean, taking less time than the
serialised process
divided by the number of cores, which is what Sean is seeing. I am not
sure I've ever seen this. Close to 1/N, sure. But 0.7/N?
Dave Riley addressed this in a later email when I wasn't looking. :)
I agree with his assessment based on my own experiences.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA