This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [Google] Adjust comdat-sharing-probability param for -Os


On Fri, Sep 27, 2013 at 4:08 PM, Xinliang David Li <davidxl@google.com> wrote:
> d.growth -= (info->size
>     * (100 - PARAM_VALUE (PARAM_COMDAT_SHARING_PROBABILITY))
>     + 50) / 100;
>
> What is the purpose of '50' here?

Rounding after division by 100.

> The patch is fine for Google branch.
>
> Other tunings to think about -- I think the sharing probability should
> not be a fixed value -- but depending on the function's charateristics
> -- such as size, number of callsites etc. For instance, for small leaf
> comdat functions, the sharing probability will be small.
> David
>
>
> On Fri, Sep 27, 2013 at 2:57 PM, Easwaran Raman <eraman@google.com> wrote:
>> This patch increases comdat-sharing-probability to 80 under -Os. This
>> reduces the amount of inlining and helps internal benchmarks.
>> Unfortunately, this causes slight regression on spec 2006. Ok for
>> google branches if all tests pass?
>>
>> - Easwaran


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]