disk I/O, VFS hirunningspace

[Alan Cox]

On Thu, Jul 15, 2010 at 8:01 AM, Ivan Voras <ivoras at freebsd.org> wrote:

> On 07/14/10 18:27, Jerry Toung wrote:
> > On Wed, Jul 14, 2010 at 12:04 AM, Gary Jennejohn
> > <gljennjohn at googlemail.com>wrote:
> >
> >>
> >>
> >> Rather than commenting out the code try setting the sysctl
> >> vfs.hirunningspace to various powers-of-two.  Default seems to be
> >> 1MB.  I just changed it on the command line as a test to 2MB.
> >>
> >> You can do this in /etc/sysctl.conf.
> >>
> >>
> > thank you all, that did it. The settings that Matt recommended are giving
> > the same numbers
>
> Any objections to raising the defaults to 8 MB / 1 MB in HEAD?
>
>
>
Keep in mind that we still run on some fairly small systems with limited I/O
capabilities, e.g., a typical arm platform.  More generally, with the range
of systems that FreeBSD runs on today, any particular choice of constants is
going to perform poorly for someone.  If nothing else, making these sysctls
a function of the buffer cache size is probably better than any particular
constants.

Alan