Re: CVS commit: [tls-maxphys] src/sys/dev

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Wed, Oct 10, 2012 at 10:48:10AM -0400, Thor Lancelot Simon wrote:
> On Wed, Oct 10, 2012 at 11:34:48AM +0200, Manuel Bouyer wrote:
> > On Tue, Oct 09, 2012 at 05:59:06PM -0700, Chuck Silvers wrote:
> > > > [...]
> > > > with a 'cat big_file > /dev/null'
> > > > writes are still limited to 64k ...
> > > 
> > > I would hope that cat'ing a file to /dev/null wouldn't result in any 
> > > writes.  :-)
> > > I assume you meant 'cat big_file > other_file' ?
> > 
> > I use: dd if=/dev/zero of=bigfile bs=1g count=7
> > 
> > > 
> > > if so, then the reason for the 64k writes would be this block of code in 
> > > ffs_write():
> > > 
> > >           if (!async && oldoff >> 16 != uio->uio_offset >> 16) {
> > >                   mutex_enter(vp->v_interlock);
> > >                   error = VOP_PUTPAGES(vp, (oldoff >> 16) << 16,
> > >                       (uio->uio_offset >> 16) << 16,
> > >                       PGO_CLEANIT | PGO_JOURNALLOCKED | PGO_LAZY);
> > >                   if (error)
> > >                           break;
> > >           }
> > > 
> > 
> > that's it. I did s/16/32/g in the code above and now I get 128k writes.
> 
> 32?  Not 17?

Yes, it was 17, of course.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
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