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

[Thor Lancelot Simon <tls%panix.com@localhost>]

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?

Thor