Re: [PATCH] wireless: iwlegacy: make const array static to shink object code size Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit
From: Julia Lawall <hidden>
Date: 2017-09-22 10:54:53
Also in:
kernel-janitors, linux-wireless, lkml
On Fri, 22 Sep 2017, Joe Perches wrote:
On Fri, 2017-09-22 at 12:06 +0200, Julia Lawall wrote:quoted
On Fri, 22 Sep 2017, Colin Ian King wrote:quoted
On 22/09/17 11:03, Joe Perches wrote:quoted
On Fri, 2017-09-22 at 09:23 +0200, Julia Lawall wrote:quoted
On Thu, 21 Sep 2017, Colin King wrote:quoted
From: Colin Ian King <redacted> Don't populate const array ac_to_fifo on the stack in an inlined function, instead make it static. Makes the object code smaller by over 800 bytes: text data bss dec hex filename 159029 33154 1216 193399 2f377 4965-mac.o text data bss dec hex filename 158122 33250 1216 192588 2f04c 4965-mac.o (gcc version 7.2.0 x86_64)Gcc 7 must be much more aggressive about inlining than gcc 4. Here is the change that I got on this file: text data bss dec hex filename - 76346 1494 152 77992 130a8 drivers/net/wireless/intel/iwlegacy/4965-mac.o + 76298 1494 152 77944 13078 drivers/net/wireless/intel/iwlegacy/4965-mac.o decrease of 48More likely different CONFIG options. e.g. allyesconfig vs defconfig with wirelessyup, I used allyesconfigMine is also allyesconfig.Odd. Here is what I get: (Sorry, no gcc-7) gcc4: gcc-4.9 (Ubuntu 4.9.4-2ubuntu1) 4.9.4 gcc5: gcc-5 (Ubuntu 5.4.1-8ubuntu1) 5.4.1 20170304 gcc6: gcc-6 (Ubuntu 6.3.0-12ubuntu2) 6.3.0 20170406 $ size drivers/net/wireless/intel/iwlegacy/4965-mac.o* text data bss dec hex filename 118559 1766 152 120477 1d69d drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc4.allyesconfig.new 118623 1766 152 120541 1d6dd drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc4.allyesconfig.old
My gcc is 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3) You get a savings of 64 and I got a savings of 48, but it's not that big a difference, compared to what the later versions give. julia
51595 1156 0 52751 ce0f drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc4.defconfig.new 51659 1156 0 52815 ce4f drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc4.defconfig.old 141956 29790 1216 172962 2a3a2 drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc5.allyesconfig.new 142671 29702 1216 173589 2a615 drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc5.allyesconfig.old 51733 1156 0 52889 ce99 drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc5.defconfig.new 51813 1156 0 52969 cee9 drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc5.defconfig.old 152991 29790 1216 183997 2cebd drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc6.allyesconfig.new 153722 29702 1216 184640 2d140 drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc6.allyesconfig.old 51813 1156 0 52969 cee9 drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc6.defconfig.new 51893 1156 0 53049 cf39 drivers/net/wireless/intel/iwlegacy/4965-mac.o.gcc6.defconfig.old -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html