From: "Chen, Tianyang" <email@example.com> To: Dario Faggioli <firstname.lastname@example.org>, email@example.com Cc: firstname.lastname@example.org, Dagaen Golomb <email@example.com>, Meng Xu <firstname.lastname@example.org> Subject: Re: [PATCH v9]xen: sched: convert RTDS from time to event driven model Date: Wed, 16 Mar 2016 11:43:47 -0400 [thread overview] Message-ID: <56E97F33.email@example.com> (raw) In-Reply-To: <firstname.lastname@example.org> On 03/16/2016 10:25 AM, Dario Faggioli wrote: > Ok, it's about time that we deal with this changelog! > > On Mon, 2016-03-14 at 20:04 -0400, Tianyang Chen wrote: >> Budget replenishment and enforcement are separated by adding >> a replenishment timer, which fires at the next most imminent >> release time of all runnable vcpus. >> > First of all, state (quickly) the "problems". So, right now: > - the scheduler, although the algorithm is event driven by nature, > follow a time driven model (is invoked periodically!), making the > code looks unnatural; > - budget replenishment logic, budget enforcement logic and scheduling > decisions are mixed and entangled, making the code hard to > understand; > - the various queues of vcpus are scanned various times, making the > code inefficient; > > Then describe your solution. The first sentence you've got up above is > ok... > >> A replenishment queue has been added to keep track of all vcpus that >> are runnable. >> > ...and this one too. > >> The following functions have major changes to manage the >> replenishment >> events and timer. >> >> repl_handler(): It is a timer handler which is re-programmed >> to fire at the nearest vcpu deadline to replenish vcpus. >> >> rt_schedule(): picks the highest runnable vcpu based on cpu >> affinity and ret.time will be passed to schedule(). If an idle >> vcpu is picked, -1 is returned to avoid busy-waiting. repl_update() >> has been removed. >> >> rt_vcpu_wake(): when a vcpu wakes up, it tickles instead of >> picking one from the run queue. >> >> rt_context_saved(): when context switching is finished, the >> preempted vcpu will be put back into the runq. >> > This is too detailed for a changelog. If you want this information to > live somewhere (it already lives in the list archives, actually), make > a cover letter (this is just one patch, so it's not required, but > nothing forbids that). Or put it in a wiki page. Or write a blog post. > Or (which would be kind of nice) all of them! :-) > I was thinking about this as well. The wiki will look a bit outdated for RTDS if this patch goes through. Meng: Do you think we should put extra information in the wiki? Someone's gotta update it sooner or later. Thanks for the review Dario. I will put everything together soon. Tianyang _______________________________________________ Xen-devel mailing list Xenemail@example.com http://lists.xen.org/xen-devel
next prev parent reply other threads:[~2016-03-16 15:43 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-03-15 0:04 Tianyang Chen 2016-03-16 3:11 ` Meng Xu 2016-03-16 3:32 ` Chen, Tianyang 2016-03-16 3:40 ` Meng Xu 2016-03-16 10:23 ` Dario Faggioli 2016-03-16 14:20 ` Meng Xu 2016-03-16 14:44 ` Dario Faggioli 2016-03-16 20:51 ` Meng Xu 2016-03-16 14:25 ` Dario Faggioli 2016-03-16 15:43 ` Chen, Tianyang [this message] 2016-03-16 16:11 ` Dario Faggioli 2016-03-16 20:54 ` Meng Xu 2016-03-16 20:45 ` Meng Xu 2016-03-17 2:24 ` Chen, Tianyang
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