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Re: [PATCH newlib]New configuration option disable io vector buffer in Newlib
- From: Corinna Vinschen <vinschen at redhat dot com>
- To: newlib at sourceware dot org
- Date: Wed, 27 Mar 2013 10:39:42 +0100
- Subject: Re: [PATCH newlib]New configuration option disable io vector buffer in Newlib
- References: <002a01ce2a0a$96b77c90$c42675b0$ at email@example.com> <3862C5643B15B6468269546753EB2A9208493996 at BLTSXVS01 dot govsolutions dot com> <003501ce2abd$6dca67d0$495f3770$ at firstname.lastname@example.org> <20130327090655 dot GB6433 at calimero dot vinschen dot de> <004001ce2acc$9437c160$bca74420$ at email@example.com>
- Reply-to: newlib at sourceware dot org
On Mar 27 17:22, Bin Cheng wrote:
> > > Thanks for suggestions. As for the changes:
> > > For code size, this patch reduces about 2+KB text section with below
> > > command line for a simple formatted IO program:
> > > $ arm-none-eabi-gcc -mthumb -mcpu=cortex-m0 -Os -ffcuntion-sections
> > > -fdata-sections -Wl,--gc-sections -lc -lnosys -lc main.c -o main.exe
> > >
> > > The library itself is build with "-Os -ffunction-sections -fdata-sections".
> > >
> > > For performance, I measured a formatted IO test which calls lots of
> > > "snprintf" and runs for about 10Secs. Turns out this patch can improve
> > > performance about 5~6%, but I won't claim how good the patch is
> > > because it's just one use-case.
> > >
> > > As for how-to document, I am not sure how to handle it. There are a
> > > bunch of "--disable/enable-*" options, but neither HOWTO nor README mentions
> > them.
> > > Maybe we could re-factor the document and find a place to describe
> > > these options in detail.
> > Yes, that's a bummer. I think we could really need somebody who would be
> > willing to add all these options to the README file with a bit of explanation
> > what each of them is doing.
> I did investigation on how those options work before, maybe I can take this work later. I have some other patches to reduce code size, I can get back to this once I finish them.
That would be incredibly helpful. Thanks for the offer!