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Re: higher-level IO very slow with cygwin1.dll 5.10 (due to set_flags?)
On Sat, Jun 26, 2004 at 11:45:04AM -0400, Pierre A. Humblet wrote:
> On Sat, Jun 26, 2004 at 02:36:52AM -0400, Joseph wrote:
> > Thanks to those who responded to my post.
> >
> > I am not sure though if all of you read the
> > entire sequence of the thread.
> >
> > In my first post, I did attach an excerpt
> > from an strace dump of a sample program that
> > seemed to show "where the time is going".
>
> You initial accusation against set_flags was unfounded
> and led nowhere. But you have a very good point.
>
> Your "fast" program is doing reads in blocks of 1024.
> Your "slow" program is using getc.
>
> I observed that the slow program was 20 times slower
> than the fast one, even though strace showed that getc
> was properly calling read in blocks of 1024.
>
> I then noticed that getc is not implemented as a macro
> on Cygwin. It's a newlib function
As you seem to care about a 20x speed increase, you can regain the
speed by editing stdio.h, letting getc be a macro on Cygwin.
Beware, I found this:
2000-05-19 DJ Delorie <dj@cygnus.com>
* libc/include/stdio.h: no getc/putc macros for cygwin; causes
compatibility issues with different dll versions
so you may need to recompile when updating cygwin.
Pierre
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