lkml.org 
[lkml]   [2011]   [Jul]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [RFC/PULL 00/11] introduce export.h; reduce module.h usage

    * Paul Gortmaker <paul.gortmaker@windriver.com> wrote:

    > > - how much does this actually improve compile times (for a
    > > "normal" build or a "allmodconfig" one)?
    >
    > Let me run some "real world" use cases and get back to you in a
    > couple of hours with that. But Ingo's testing on a much earlier
    > snapshot was showing roughly a couple percent. (
    > https://lkml.org/lkml/2011/5/28/60 )

    I found that it's pretty hard to measure these things accurately and
    reliably, kernel build times are very noisy.

    Note that you can use my numbers to estimate expected savings: just
    build before/after .i files in a common directory like kernel/*.c and
    measure their combined size. The size decrease of the preprocessor
    output scales almost linearly with runtime.

    You could standardize on that kind of metric "these patches decrease
    preprocessor output by 0.5%" - those translate almost 1:1 into
    compile time speedups, and you don't really have to re-measure
    compile times every time you come up with such patches.

    Thanks,

    Ingo


    \
     
     \ /
      Last update: 2011-07-28 21:21    [W:2.374 / U:0.048 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site