1. 20 Aug, 2014 1 commit
  2. 07 Mar, 2010 1 commit
  3. 25 Mar, 2006 1 commit
    • Arjan van de Ven's avatar
      [PATCH] x86_64: Basic reorder infrastructure · 4bdc3b7f
      Arjan van de Ven authored
      This patch puts the infrastructure in place to allow for a reordering of
      functions based inside the vmlinux. The general idea is that it is possible
      to put all "common" functions into the first 2Mb of the code, so that they
      are covered by one TLB entry. This as opposed to the current situation where
      a typical vmlinux covers about 3.5Mb (on x86-64) and thus 2 TLB entries.
      
      This is done by enabling the -ffunction-sections flag in gcc, which puts
      each function in its own ELF section, so that the linker can then order them
      in a way defined by the linker script.
      
      As per previous discussions, Linus said he wanted a "static" list for this,
      eg a list provided by the kernel tarbal, so that most people have the same
      ordering at least. A script is provided to create this list based on
      readprofile(1) output. The included list is provisional, and entirely biased
      on my own testbox and me running a few kernel compiles and some other
      things.
      
      I think that to get to a better list we need to invite people to submit
      their own profiles, and somehow add those all up and base the final list on
      that. I'm willing to do that effort if this is ends up being the prefered
      approach. Such an effort probably needs to be repeated like once a year or
      so to adopt to the changing nature of the kernel.
      
      Made it a CONFIG with default n because it increases link times
      dramatically.
      Signed-off-by: default avatarAndi Kleen <ak@suse.de>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      4bdc3b7f