Re: Quantitative analysis of -Os vs -O3

2017-08-27 Thread Andi Kleen
Allan Sandfeld Jensen writes: > > Yeah. That is just more problematic in practice. Though I do believe we have > support for it. It is good to know it will automatically upgrade > optimizations > like that. I just wish there was a way to distribute pre-generated arch- >

Re: Quantitative analysis of -Os vs -O3

2017-08-26 Thread Michael Clark
FYI - I’ve updated the stats to include -O2 in addition to -O3 and -Os: - https://rv8.io/bench#optimisation There are 57 plots and 31 tables. It’s quite a bit of data. It will be quite interesting to run these on new gcc releases to monitor changes. The Geomean for -O2 is 0.98 of -O3 on

Re: Quantitative analysis of -Os vs -O3

2017-08-26 Thread Allan Sandfeld Jensen
On Samstag, 26. August 2017 12:59:06 CEST Markus Trippelsdorf wrote: > On 2017.08.26 at 12:40 +0200, Allan Sandfeld Jensen wrote: > > On Samstag, 26. August 2017 10:56:16 CEST Markus Trippelsdorf wrote: > > > On 2017.08.26 at 01:39 -0700, Andrew Pinski wrote: > > > > First let me put into some

Re: Quantitative analysis of -Os vs -O3

2017-08-26 Thread Markus Trippelsdorf
On 2017.08.26 at 12:40 +0200, Allan Sandfeld Jensen wrote: > On Samstag, 26. August 2017 10:56:16 CEST Markus Trippelsdorf wrote: > > On 2017.08.26 at 01:39 -0700, Andrew Pinski wrote: > > > First let me put into some perspective on -Os usage and some history: > > > 1) -Os is not useful for

Re: Quantitative analysis of -Os vs -O3

2017-08-26 Thread Allan Sandfeld Jensen
On Samstag, 26. August 2017 10:56:16 CEST Markus Trippelsdorf wrote: > On 2017.08.26 at 01:39 -0700, Andrew Pinski wrote: > > First let me put into some perspective on -Os usage and some history: > > 1) -Os is not useful for non-embedded users > > 2) the embedded folks really need the smallest

Re: Quantitative analysis of -Os vs -O3

2017-08-26 Thread Michael Clark
> On 26 Aug 2017, at 8:39 PM, Andrew Pinski wrote: > > On Sat, Aug 26, 2017 at 1:23 AM, Michael Clark wrote: >> Dear GCC folk, >> I have to say that’s GCC’s -Os caught me by surprise after several years >> using Apple GCC and more recently LLVM/Clang

RE: Quantitative analysis of -Os vs -O3

2017-08-26 Thread Shi, Steven
> 4) -Os is used heavily by the arm/thumb2 folks in bare metal applications. Also by the x86 in bare-mental firmware, e.g. http://www.uefi.org/ > For many applications using -flto does reduce code size more than just > going from -O2 to -Os. Yes. -flto is must to have, but the -Os is still

Re: Quantitative analysis of -Os vs -O3

2017-08-26 Thread Markus Trippelsdorf
On 2017.08.26 at 01:39 -0700, Andrew Pinski wrote: > > First let me put into some perspective on -Os usage and some history: > 1) -Os is not useful for non-embedded users > 2) the embedded folks really need the smallest code possible and > usually will be willing to afford the performance hit >

Re: Quantitative analysis of -Os vs -O3

2017-08-26 Thread Andrew Pinski
On Sat, Aug 26, 2017 at 1:23 AM, Michael Clark wrote: > Dear GCC folk, > I have to say that’s GCC’s -Os caught me by surprise after several years > using Apple GCC and more recently LLVM/Clang in Xcode. Over the last year and > a half I have been working on RISC-V

Quantitative analysis of -Os vs -O3

2017-08-26 Thread Michael Clark
Dear GCC folk, I have to say that’s GCC’s -Os caught me by surprise after several years using Apple GCC and more recently LLVM/Clang in Xcode. Over the last year and a half I have been working on RISC-V development and have been exclusively using GCC for RISC-V builds, and initially I was