Messages in this thread | | | Subject | Re: [patch 00/2] improve .text size on gcc 4.0 and newer compilers | From | Alan Cox <> | Date | Fri, 30 Dec 2005 15:28:00 +0000 |
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On Mer, 2005-12-28 at 20:11 -0800, Andrew Morton wrote: > If no-forced-inlining makes the kernel smaller then we probably have (yet > more) incorrect inlining. We should hunt those down and fix them. We did > quite a lot of this in 2.5.x/2.6.early. Didn't someone have a script which > would identify which functions are a candidate for uninlining?
There is a tool that does this quite well. Its called "gcc" ;)
More seriously we need to seperate "things Andrew thinks are good inline candidates" and "things that *must* be inlined". That allows 'build for size' to do the equivalent of "-Dplease_inline" and the other build to do "-Dplease_inline=inline". Gcc's inliner isn't aware of things cross module so isn't going to make all the decisions right, but will make the tedious local decisions.
As far as bugs go - gcc -Os has also fixed bugs in the past. It doesn't introduce bugs so much as change them. Fedora means we have good long term data on -Os with modern gcc (not with old gcc but we just dumped < 3.2 anyway).
Nowdays the -Os code paths are also getting real hammering because many people build desktops, even OpenOffice with -Os and see overall performance gains for the system.
Alan
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