Re: [perl #122955] [PATCH] speed up building with less disk IO podmoves+__END__+misc

On Sun, 12 Oct 2014 20:30:34 -0500, "Craig A. Berry"
<craig.a.berry@gmail.com> wrote:

> On Sun, Oct 12, 2014 at 7:53 PM, Father Chrysostomos via RT
> <perlbug-followup@perl.org> wrote:
> 
> >> I'd considered reading perl source with a buffer size of 4096 to be a
> >> bug in itself.
> >
> > Could you clarify?
> 
> Reading 4K at a time off disk is going to be inefficient compared to
> reading larger chunks, especially if we're stopping to expand memory
> and/or percolate up through the perlio layers each time.  When using
> perlio, the perlio buffer should be the larger of 8192 and BUFSIZ,
> which increased speed dramatically compare to 4K buffers.  See
> 
> http://perl5.git.perl.org/perl.git/commitdiff/b83080de5c42543809ce9004bcdbcd3162a00e70
>
> Of course 8K is pretty small by today's standards so that could
> probably be revisited.  One of the problems is that the buffer is the
> same size regardless of whether we're reading off disk or through a
> pipe.  And what's optimal for reading files in general may or may not
> be optimal for reading Perl source.

I did a quick inventory of all local mounted file systems on HP-UX
I explicitly excluded /stand (linux-talk /boot) as that seems to have
a larger block-size than the other FS's

All HP-UX versions have 1024 as BUFSIZE in /usr/include/stdio.h

         bsize   /stand
10.20:   1024      8192 (PA2)
11.00:   8192     65536 (PA2)
11.11:   8192     65536 (PA2)
11.23:   8192     65536 (PA2)
11.23:   8192      8192 (IPF)
11.31:   8192      8192 (IPF)

# di -l | perl -ne'm{^(/dev\S+)\s+(\S+)} and print "$1\t$2\t", grep /bsize/ => `fstyp -v $1\n`'
/dev/vg00/lvol3 /       f_bsize: 8192
/dev/vg00/data  /data   f_bsize: 8192
/dev/vg00/home  /home   f_bsize: 8192
/dev/vg00/opt   /opt    f_bsize: 8192
/dev/vg00/pro   /pro    f_bsize: 8192
/dev/vg00/prodb /prodb  f_bsize: 8192
/dev/vg00/lvol1 /stand  f_bsize: 8192
/dev/vg00/tmp   /tmp    f_bsize: 8192
/dev/vg00/usr   /usr    f_bsize: 8192
/dev/vg00/lvol8 /var    f_bsize: 8192
/dev/vg00/wrk   /wrk    f_bsize: 8192


-- 
H.Merijn Brand  http://tux.nl   Perl Monger  http://amsterdam.pm.org/
using perl5.00307 .. 5.19   porting perl5 on HP-UX, AIX, and openSUSE
http://mirrors.develooper.com/hpux/        http://www.test-smoke.org/
http://qa.perl.org   http://www.goldmark.org/jeff/stupid-disclaimers/

• [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by Father Chrysostomos via RT
• [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by bulk88 via RT
• [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by bulk88 via RT
• [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by Father Chrysostomos via RT
• Re: [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by Craig A. Berry
• Re: [perl #122955] [PATCH] speed up building with less disk IO podmoves+__END__+misc by H.Merijn Brand
• Re: [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by Craig A. Berry
• [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by Tony Cook via RT
• [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by Father Chrysostomos via RT
• [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by bulk88 via RT
• [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by Father Chrysostomos via RT
• [perl #122955] [PATCH] speed up building with less disk IO pod moves+__END__+misc by bulk88