On Sat, Jul 22, 2017 at 02:16:41PM -0400, Theodore Ts'o wrote:
> On Fri, Jul 21, 2017 at 04:55:12PM +0200, Oliver Mangold wrote:
> > On 21.07.2017 16:47, Theodore Ts'o wrote:
> > > On Fri, Jul 21, 2017 at 01:39:13PM +0200, Oliver Mangold wrote:
> > > > Better, but obviously there is still much room
On Fri, Jul 21, 2017 at 04:55:12PM +0200, Oliver Mangold wrote:
> On 21.07.2017 16:47, Theodore Ts'o wrote:
> > On Fri, Jul 21, 2017 at 01:39:13PM +0200, Oliver Mangold wrote:
> > > Better, but obviously there is still much room for improvement by reducing
> > > the number of calls to RDRAND.
> > H
On 07/21/2017 09:47 AM, Theodore Ts'o wrote:
On Fri, Jul 21, 2017 at 01:39:13PM +0200, Oliver Mangold wrote:
Better, but obviously there is still much room for improvement by reducing
the number of calls to RDRAND.
Hmm, is there some way we can easily tell we are running on Ryzen? Or
do we be
On 21.07.2017 16:47, Theodore Ts'o wrote:
On Fri, Jul 21, 2017 at 01:39:13PM +0200, Oliver Mangold wrote:
Better, but obviously there is still much room for improvement by reducing
the number of calls to RDRAND.
Hmm, is there some way we can easily tell we are running on Ryzen? Or
do we believ
On Fri, Jul 21, 2017 at 01:39:13PM +0200, Oliver Mangold wrote:
> Better, but obviously there is still much room for improvement by reducing
> the number of calls to RDRAND.
Hmm, is there some way we can easily tell we are running on Ryzen? Or
do we believe this is going to be true for all AMD de
On Fri, Jul 21, 2017 at 3:12 AM, Oliver Mangold wrote:
> Hi,
>
> I was wondering why reading from /dev/urandom is much slower on Ryzen than
> on Intel, and did some analysis. It turns out that the RDRAND instruction is
> at fault, which takes much longer on AMD.
>
> if I read this correctly:
>
> -
On 21.07.2017 11:26, Jan Glauber wrote:
Nice catch. How much does the performance improve on Ryzen when you
use arch_get_random_int()?
Okay, now I have some results for you:
On Ryzen 1800X (using arch_get_random_int()):
---
# dd if=/dev/urandom of=/dev/null bs=1M status=progress
8751415296 b
On Fri, Jul 21, 2017 at 09:12:01AM +0200, Oliver Mangold wrote:
> Hi,
>
> I was wondering why reading from /dev/urandom is much slower on
> Ryzen than on Intel, and did some analysis. It turns out that the
> RDRAND instruction is at fault, which takes much longer on AMD.
>
> if I read this correc