Btw, I was curious, so I just looked at the difference between /O1 (size) and /O2 (speed) and /Ox (full)
/O1 (Minimize Size) /Og /Os /Oy /Ob2 /Gs /GF /Gy /O2 (Maximize Speed) /Og /Oi /Ot /Oy /Ob2 /Gs /GF /Gy So the difference is the addition of /Oi, and /Ot. The /Oi means things like, you can generate rep scansb instructions instead of strlen, and rep movsd/movsb instead of memcpy, etc. The /Ot means favor speed over size. I am not so sure about that one. This is effectively the same as what we were doing with /Ox. I would be interesting in seeing how /O1 compares? And also the combination of /O1 + /Oi, which should give some good performance and a bit of size cost. I think theoretically what we want is /O1, or /O1 /Oi, but we'd need to look at the numbers of performance vs code size. Thanks - dean On Thu, Oct 2, 2008 at 10:44 AM, <[EMAIL PROTECTED]> wrote: > > Reviewers: Christian Plesner Hansen, > > Description: > Changed optimization from /Ox to the (more) commonly used /O2 (which > includes > /GF) in both SCons and Visual Studio build. There is not mesurable > difference > neither in speed nor in code size. > > Added whole program optimization to the SCons release build. This > clutters the > linking of the samples a little with the option /LTCG. This option is > not > strictly needed for linking, but if it is not specified the linker > complaints > as it can see object files compiled with /GL and then restarts itself > with > /LTCG which dosen't look very pretty. > > Please review this at http://codereview.chromium.org/5664 > > Affected files: > M SConstruct > M tools/visual_studio/release.vsprops > > > Index: tools/visual_studio/release.vsprops > =================================================================== > --- tools/visual_studio/release.vsprops (revision 404) > +++ tools/visual_studio/release.vsprops (working copy) > @@ -7,7 +7,7 @@ > <Tool > Name="VCCLCompilerTool" > RuntimeLibrary="0" > - Optimization="3" > + Optimization="2" > InlineFunctionExpansion="2" > EnableIntrinsicFunctions="true" > FavorSizeOrSpeed="0" > Index: SConstruct > =================================================================== > --- SConstruct (revision 404) > +++ SConstruct (working copy) > @@ -77,8 +77,9 @@ > 'LINKFLAGS': ['/DEBUG'] > }, > 'mode:release': { > - 'CCFLAGS': ['/Ox', '/MT', '/GF'], > - 'LINKFLAGS': ['/OPT:REF', '/OPT:ICF'] > + 'CCFLAGS': ['/O2', '/MT', '/GL'], > + 'LINKFLAGS': ['/OPT:REF', '/OPT:ICF', '/LTCG'], > + 'ARFLAGS': ['/LTCG'] > } > } > } > @@ -205,8 +206,8 @@ > 'LINKFLAGS': ['/MAP'] > }, > 'mode:release': { > - 'CCFLAGS': ['/Ox', '/MT', '/GF'], > - 'LINKFLAGS': ['/OPT:REF', '/OPT:ICF'] > + 'CCFLAGS': ['/O2', '/MT'], > + 'LINKFLAGS': ['/OPT:REF', '/OPT:ICF', '/LTCG'] > }, > 'mode:debug': { > 'CCFLAGS': ['/Od', '/MTd'], > > > > > > --~--~---------~--~----~------------~-------~--~----~ v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev -~----------~----~----~----~------~----~------~--~---
