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Re: [Google] Adjust comdat-sharing-probability param for -Os
- From: Xinliang David Li <davidxl at google dot com>
- To: Easwaran Raman <eraman at google dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 27 Sep 2013 16:08:47 -0700
- Subject: Re: [Google] Adjust comdat-sharing-probability param for -Os
- Authentication-results: sourceware.org; auth=none
- References: <CAPK5YPZ-84Sfa_tB7-UONDA_r6+UN25wkfp6WZ4suMF30wamrw at mail dot gmail dot com>
d.growth -= (info->size
* (100 - PARAM_VALUE (PARAM_COMDAT_SHARING_PROBABILITY))
+ 50) / 100;
What is the purpose of '50' here?
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.
On Fri, Sep 27, 2013 at 2:57 PM, Easwaran Raman <email@example.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