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Re: What makes a difference in the resulting compiler's speed when building gcc?
On 27/10/16 17:30, Marc Glisse wrote:
On Thu, 27 Oct 2016, Sven C. Dack wrote:
I've been installing private copies of gcc for a while now, but only recently
did I notice that my distro's gcc (Debian testing) is doing much better when
comparing compile times than any of my copies. For instance does it take 230s
for my copy to compile a linux kernel, but only 163s for my distro's gcc,
which is almost a minute in difference for something that doesn't take more
than 3-4 minutes to compile.
What makes this noteworthy for me is that I've compiled my copy with
profiledbootstrap and LTO enabled and also optimized it for my CPU, whereas
the distro's compiler won't have been optimized quite that much, but yet is
it so much faster in speed. I don't know how exactly my distro's gcc has been
set up, because the Debian build rules are rather complex and include their
own set of patches. So I thought I start with asking here first.
What is that can make such a huge difference in compile speed for two copies
of gcc, both version 6.2, using the same options, on the same source? Or are
any of the configure options know to have a huge impact on the resulting
compiler's speed?
--enable-checking=release would be the first thing to check.
Thank you, will do.
I can already say that I am using "yes", because I'm using the latest git
versions and have always favoured a reasonable amount of checks. If this is
already the cause for the difference then I might actually keep it this way.