Re: [PATCH] [RFC] notify userspace about time changes

From: Alexander Shishkin
Date: Thu Aug 05 2010 - 08:39:37 EST

On 5 August 2010 03:52, john stultz <johnstul@xxxxxxxxxx> wrote:
> On Wed, 2010-08-04 at 12:48 -0600, Chris Friesen wrote:
>> On 08/04/2010 09:58 AM, john stultz wrote:
>> > Is there a actual use case that you need this for? ÂI don't really have
>> > an issue with the code I just really want to make sure the feature would
>> > be useful enough to justify the API and code maintenance going forward.
>> We actually added a time-change-notification mechanism internally a long
>> time ago but never saw demand for it and so never bothered trying to
>> push it upstream. ÂOurs is signal-based.
>> Among other things we use it to pass on time-change notifications to an
>> emulator running a proprietary OS that really cares about having an
>> accurate time-of-day but can't afford a syscall to retrieve it every time.
> So the eventfd based method (and the filtering) proposed would work for
> you?

I think that Kirill has a point and the filtering is really there for
no gain. The user
can indeed count his own time changes and compare that against the eventfd

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