From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from feline.systems ([99.23.220.214]) by ewsd; Sun Aug 12 18:28:34 EDT 2018
Date: Sun, 12 Aug 2018 22:28:28 +0000
From: BurnZeZ@feline.systems
To: 9front@9front.org
Subject: Re: [9front] time
Message-ID: <6c11e603325ca644a5068fd3d0f30df1@rebk.znet>
In-Reply-To: <543D9EFF84178350A65D710955EDB98B@felloff.net>
References: <543D9EFF84178350A65D710955EDB98B@felloff.net>
MIME-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
List-ID: <9front.9front.org>
List-Help: <http://lists.9front.org>
X-Glyph: ➈
X-Bullshit: abstract blockchain base YAML configuration cloud 

On Sun Aug 12 21:08:00 GMT 2018, cinap_lenrek@felloff.net wrote:
> of course it does. theres nothing special about exec. the accounting
> starts when the *process* is created, not after exec(). also, it is
> hard to know what you consider time spend execing. the exec itself
> just reads the programs a.out header and creates the segments.
> the pages get faulted in during the runtime of the program *after*
> exec did its job.

I’ve been tricked.


> internally, user/kernel time accounting works by hzclock()
> just incrementing a per process counter of ticks. which is
> not very precise and processes can evade time being accounted
> by yielding so they'd miss the timer interrupt.

Are there any other reasons for the real time count to become erratic
or inconsistent?
How does this work on a multi-core machine?


> so there is an opportunity here that when going to 64 bit,
> we could improve the time accounting and change the unit
> to nanoseconds as well...

Might be better than staying with milli, since nsec() sort of
promotes nano anyway.