[PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-13 Thread Artem S. Tashkinov
> GCC 10 appears to have changed -O2 in order to make compilation time faster when using -flto, seemingly at the expense of performance, in particular with regards to how the inliner works. Since -O3 these days shouldn't have the same set of bugs as 10 years ago, this commit defaults new kernel

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-11 Thread Masahiro Yamada
On Sun, May 10, 2020 at 9:47 PM David Laight wrote: > > From: Joe Perches > > Sent: 08 May 2020 16:06 > > On Fri, 2020-05-08 at 13:49 +0200, Arnd Bergmann wrote: > > > Personally, I'm more interested in improving compile speed of the kernel > > > > Any opinion on precompiled header support? > >

RE: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-10 Thread David Laight
From: Joe Perches > Sent: 10 May 2020 18:45 > > On Sun, 2020-05-10 at 12:47 +, David Laight wrote: > > From: Joe Perches > > > Sent: 08 May 2020 16:06 > > > On Fri, 2020-05-08 at 13:49 +0200, Arnd Bergmann wrote: > > > > Personally, I'm more interested in improving compile speed of the kernel

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-10 Thread Joe Perches
On Sun, 2020-05-10 at 12:47 +, David Laight wrote: > From: Joe Perches > > Sent: 08 May 2020 16:06 > > On Fri, 2020-05-08 at 13:49 +0200, Arnd Bergmann wrote: > > > Personally, I'm more interested in improving compile speed of the kernel > > > > Any opinion on precompiled header support? > >

RE: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-10 Thread David Laight
From: Joe Perches > Sent: 08 May 2020 16:06 > On Fri, 2020-05-08 at 13:49 +0200, Arnd Bergmann wrote: > > Personally, I'm more interested in improving compile speed of the kernel > > Any opinion on precompiled header support? When ever I've been anywhere near it it is always a disaster. It may

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-08 Thread Arnd Bergmann
On Fri, May 8, 2020 at 5:06 PM Joe Perches wrote: > > On Fri, 2020-05-08 at 13:49 +0200, Arnd Bergmann wrote: > > Personally, I'm more interested in improving compile speed of the kernel > > Any opinion on precompiled header support? I have not tried it. IIRC precompiled headers usually work

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-08 Thread Joe Perches
On Fri, 2020-05-08 at 13:49 +0200, Arnd Bergmann wrote: > Personally, I'm more interested in improving compile speed of the kernel Any opinion on precompiled header support?

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-08 Thread Arnd Bergmann
On Fri, May 8, 2020 at 2:07 PM Jason A. Donenfeld wrote: > On Fri, May 8, 2020 at 5:56 AM Arnd Bergmann wrote: > > The other significant thing -- and what prompted this patchset -- is > it looks like gcc 10 has lowered the inlining degree for -O2, and put > gcc 9's inlining parameters from -O2

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-08 Thread Jason A. Donenfeld
On Fri, May 8, 2020 at 5:56 AM Arnd Bergmann wrote: > > On Fri, May 8, 2020 at 1:33 PM Oleksandr Natalenko > wrote: > > > > On Fri, May 08, 2020 at 05:21:47AM -0600, Jason A. Donenfeld wrote: > > > > Should we untangle -O3 from depending on ARC first maybe? > > > > > > Oh, hah, good point. Yes,

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-08 Thread Arnd Bergmann
On Fri, May 8, 2020 at 1:33 PM Oleksandr Natalenko wrote: > > On Fri, May 08, 2020 at 05:21:47AM -0600, Jason A. Donenfeld wrote: > > > Should we untangle -O3 from depending on ARC first maybe? > > > > Oh, hah, good point. Yes, I'll do that for a v2, but will wait another > > day for feedback

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-08 Thread Oleksandr Natalenko
On Fri, May 08, 2020 at 05:21:47AM -0600, Jason A. Donenfeld wrote: > > Should we untangle -O3 from depending on ARC first maybe? > > Oh, hah, good point. Yes, I'll do that for a v2, but will wait another > day for feedback first. Just keep in mind that my previous attempt [1] failed because of

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-08 Thread Jason A. Donenfeld
On Fri, May 8, 2020 at 3:08 AM Oleksandr Natalenko wrote: > > Should we untangle -O3 from depending on ARC first maybe? Oh, hah, good point. Yes, I'll do that for a v2, but will wait another day for feedback first. Jason

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-08 Thread Oleksandr Natalenko
On Thu, May 07, 2020 at 04:45:30PM -0600, Jason A. Donenfeld wrote: > GCC 10 appears to have changed -O2 in order to make compilation time > faster when using -flto, seemingly at the expense of performance, in > particular with regards to how the inliner works. Since -O3 these days > shouldn't

Re: [PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-08 Thread Peter Zijlstra
On Thu, May 07, 2020 at 04:45:30PM -0600, Jason A. Donenfeld wrote: > GCC 10 appears to have changed -O2 in order to make compilation time > faster when using -flto, seemingly at the expense of performance, in > particular with regards to how the inliner works. Since -O3 these days > shouldn't

[PATCH] Kconfig: default to CC_OPTIMIZE_FOR_PERFORMANCE_O3 for gcc >= 10

2020-05-07 Thread Jason A. Donenfeld
GCC 10 appears to have changed -O2 in order to make compilation time faster when using -flto, seemingly at the expense of performance, in particular with regards to how the inliner works. Since -O3 these days shouldn't have the same set of bugs as 10 years ago, this commit defaults new kernel