* Re: eliminate -pipe from kernel compile [not found] <20090511015831.GB15777@luminet.net> @ 2009-05-11 6:02 ` Geert Uytterhoeven 2009-05-13 0:38 ` Sam Ravnborg 0 siblings, 1 reply; 3+ messages in thread From: Geert Uytterhoeven @ 2009-05-11 6:02 UTC (permalink / raw) To: lancetag, linux-m68k; +Cc: linux-kbuild Added linux-kbuild On Mon, May 11, 2009 at 03:58, Lance Tagliapietra <lancetag@luminet.net> wrote: > I was noticing that kernel compiling is set up to have gcc pipe data from one pass to another, instead of using > temporary files. On a memory constrained environment, this may not be the best idea (or at least I'd like to > explore that idea). Instead of loading the assember, and having immediately being swapped out while the cc1 pass > runs, it may make more sense to have the temp files being written, instead of the swap in and out, when compiling > the various objects of the kernel. > > So, simply pulling out the -pipe from the compiler flag list didn't see to have the desired effect. I'm afraid I'm > still missing something. I'm still observing the assembler being loaded. > > Thoughts? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: eliminate -pipe from kernel compile 2009-05-11 6:02 ` eliminate -pipe from kernel compile Geert Uytterhoeven @ 2009-05-13 0:38 ` Sam Ravnborg 2009-05-14 3:12 ` Lance Tagliapietra 0 siblings, 1 reply; 3+ messages in thread From: Sam Ravnborg @ 2009-05-13 0:38 UTC (permalink / raw) To: Geert Uytterhoeven, Lance Tagliapietra; +Cc: linux-m68k, linux-kbuild On Mon, May 11, 2009 at 08:02:16AM +0200, Geert Uytterhoeven wrote: > Added linux-kbuild > > On Mon, May 11, 2009 at 03:58, Lance Tagliapietra <lancetag@luminet.net> wrote: > > I was noticing that kernel compiling is set up to have gcc pipe data from one pass to another, instead of using > > temporary files. On a memory constrained environment, this may not be the best idea (or at least I'd like to > > explore that idea). Instead of loading the assember, and having immediately being swapped out while the cc1 pass > > runs, it may make more sense to have the temp files being written, instead of the swap in and out, when compiling > > the various objects of the kernel. > > > > So, simply pulling out the -pipe from the compiler flag list didn't see to have the desired effect. I'm afraid I'm > > still missing something. I'm still observing the assembler being loaded. 1) How did you "pulling out the -pipe from the compiler flag list"? Please show this as a patch. 2) Did you verify that -pipe was used before and no more after your changes? Hint - use "make V=1" to see all command line options to gcc Sam ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: eliminate -pipe from kernel compile 2009-05-13 0:38 ` Sam Ravnborg @ 2009-05-14 3:12 ` Lance Tagliapietra 0 siblings, 0 replies; 3+ messages in thread From: Lance Tagliapietra @ 2009-05-14 3:12 UTC (permalink / raw) To: Sam Ravnborg; +Cc: Geert Uytterhoeven, linux-m68k, linux-kbuild Hello, I just completed a test build with my patch to arch/m68k/Makefile to remove the -pipe flag (see patch below). Watching the build confirmed that a) -pipe was no longer showing up in the gcc command lines and b) temporary files were being created as expected without pipe; and c) the as command was not loaded waiting for cc1 to complete. Yea! The /arch/m68k/Makefile is the only place where the -pipe flag is located, and that seems to be the place for all arch's. --- arch/m68k/Makefile.old 2009-05-13 21:58:28.000000000 -0500 +++ arch/m68k/Makefile 2009-05-09 11:16:39.000000000 -0500 @@ -33,7 +33,9 @@ CHECKFLAGS += -D__mc68000__ # without -fno-strength-reduce the 53c7xx.c driver fails ;-( -KBUILD_CFLAGS += -pipe -fno-strength-reduce -ffixed-a2 +# delete -pipe to save RAM / minimize swap during compile +# original: KBUILD_CFLAGS += -pipe -fno-strength-reduce -ffixed-a2 +KBUILD_CFLAGS += -fno-strength-reduce -ffixed-a2 # enable processor switch if compiled only for a single cpu ifndef CONFIG_M68020 Pulling out the -pipe does seem to cut compile time. I am working on hard numbers. --Lance On Wed, May 13, 2009 at 02:38:29AM +0200, Sam Ravnborg wrote: > On Mon, May 11, 2009 at 08:02:16AM +0200, Geert Uytterhoeven wrote: > > Added linux-kbuild > > > > On Mon, May 11, 2009 at 03:58, Lance Tagliapietra <lancetag@luminet.net> wrote: > > > I was noticing that kernel compiling is set up to have gcc pipe data from one pass to another, instead of using > > > temporary files. ?On a memory constrained environment, this may not be the best idea (or at least I'd like to > > > explore that idea). ?Instead of loading the assember, and having immediately being swapped out while the cc1 pass > > > runs, it may make more sense to have the temp files being written, instead of the swap in and out, when compiling > > > the various objects of the kernel. > > > > > > So, simply pulling out the -pipe from the compiler flag list didn't see to have the desired effect. ?I'm afraid I'm > > > still missing something. ?I'm still observing the assembler being loaded. > > 1) How did you "pulling out the -pipe from the compiler flag list"? > Please show this as a patch. > > 2) Did you verify that -pipe was used before and no more after your > changes? > Hint - use "make V=1" to see all command line options to gcc > > Sam ^ permalink raw reply [flat|nested] 3+ messages in thread
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2009-05-11 6:02 ` eliminate -pipe from kernel compile Geert Uytterhoeven
2009-05-13 0:38 ` Sam Ravnborg
2009-05-14 3:12 ` Lance Tagliapietra
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