[openstack-dev] [nova][keystone] Message Queue Security

Joshua Harlow harlowja at yahoo-inc.com
Thu Apr 25 19:39:19 UTC 2013

Except there is concurrency, eventlet just makes it 'appear' that there

Right now any blocking operation will cause a context-switch, think of
that as the trigger to cause said context-switch.

In regular process schedulers there is just a different trigger that the
operating system uses.

So to me we already have concurrency (not for simple int operations of
course), its just sorta ghetto :-P

On 4/25/13 9:27 AM, "Simo Sorce" <simo at redhat.com> wrote:

>On Thu, 2013-04-25 at 17:19 +0100, David Chadwick wrote:
>> What happens in a very fast system if two sub-processes create a
>> at the same time and therefore contain the same timestamp?
>Well, right now we use eventlet so no concurrency is really allowed.
>If we move to a truly concurrent system (something I actually hope we
>do) then we'll have to serialize how we get the timestamp. We'll
>basically need a single source of time that will just increment by one
>hundredth of a second or so if a second request comes in within the same
>hundredth of a second. Basically keep a high watermark in shared memory
>and use atomic updates to never get a dup.
>Simo Sorce * Red Hat, Inc * New York
>OpenStack-dev mailing list
>OpenStack-dev at lists.openstack.org

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