lkml.org 
[lkml]   [2005]   [Sep]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2.6.13] IOCHK interface for I/O error handling/detecting (for ia64)
On 9/2/05, Grant Grundler <iod00d@hp.com> wrote:
> On Thu, Sep 01, 2005 at 05:45:54PM -0500, Brent Casavant wrote:
> ...
> > The first is serialization of all I/O reads and writes. This will
> > be a severe problem on systems with large numbers of PCI buses, the
> > very type of system that stands the most to gain in reliability from
> > these efforts. At a minimum any locking should be done on a per-bus
> > basis.
>
> The lock could be per "error domain" - that would require some
> arch specific support though to define the scope of the "error domain".

I do not think the basic inX/outX and readX/writeX operations should
involve spinlocks. That would be really nasty if an MCA/INIT handler
had to call them, for example...

> > The second is the raw performance penalty from acquiring and dropping
> > a lock with every read and write. This will be a substantial amount
> > of activity for any I/O-intensive system, heck even for moderate I/O
> > levels.
>
> Sorry - I think this is BS.
>
> Please run mmio_test on your box and share the results.
> mmio_test is available here:
> svn co http://svn.gnumonks.org/trunk/mmio_test/

Reads are slow, sure, but writes are not (or should not).

--david
--
Mosberger Consulting LLC, voice/fax: 510-744-9372,
http://www.mosberger-consulting.com/
35706 Runckel Lane, Fremont, CA 94536
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-09-02 20:18    [W:0.060 / U:0.564 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site