(original) (raw)

changeset: 103334:e1987bf14148 branch: 3.5 parent: 103312:4f6fef83cd0c user: Gregory P. Smith greg@krypto.org [Google Inc.] date: Thu Sep 08 18:33:00 2016 +0000 files: README description: document --with-optimizations in the README for issue26359. diff -r 4f6fef83cd0c -r e1987bf14148 README --- a/README Thu Sep 08 19:40:30 2016 +0300 +++ b/README Thu Sep 08 18:33:00 2016 +0000 @@ -46,16 +46,17 @@ (This will fail if you *also* built at the top-level directory. You should do a "make clean" at the toplevel first.) -If you need an optimized version of Python, you type "make profile-opt" in the -top level directory. This will rebuild the interpreter executable using Profile -Guided Optimization (PGO). For more details, see the section bellow. +To get an optimized build of Python, "configure --with-optimizations" before +you run make. This sets the default make targets up to enable Profile Guided +Optimization (PGO) and Link Time Optimization (LTO) on most platforms. +For more details, see the sections bellow. Profile Guided Optimization --------------------------- PGO takes advantage of recent versions of the GCC or Clang compilers. -If ran, the "profile-opt" rule will do several steps. +If ran, "make profile-opt" will do several steps. First, the entire Python directory is cleaned of temporary files that may have resulted in a previous compilation. @@ -75,6 +76,14 @@ that is optimized and suitable for distribution or production installation. +Link Time Optimization +---------------------- + +LTO takes advantages of recent compiler toolchains ability to optimize across +the otherwise arbitrary .o file boundary when building final executables or +shared libraries for additional performance gains. + + What's New ---------- /greg@krypto.org