All of lore.kernel.org
 help / color / mirror / Atom feed
From: Dario Faggioli <dario.faggioli@citrix.com>
To: anshul makkar <anshul.makkar@citrix.com>, xen-devel@lists.xenproject.org
Cc: "Justin T. Weaver" <jtweaver@hawaii.edu>,
	George Dunlap <george.dunlap@citrix.com>
Subject: Re: [PATCH 17/24] xen: credit2: soft-affinity awareness in runq_tickle()
Date: Wed, 7 Sep 2016 15:31:44 +0200	[thread overview]
Message-ID: <1473255104.19612.125.camel@citrix.com> (raw)
In-Reply-To: <57D01518.1090006@citrix.com>


[-- Attachment #1.1: Type: text/plain, Size: 1754 bytes --]

On Wed, 2016-09-07 at 14:24 +0100, anshul makkar wrote:
> On 05/09/16 15:55, Dario Faggioli wrote:
> > On Thu, 2016-09-01 at 11:52 +0100, anshul makkar wrote:
> > So, yes, we know already that it's running in a cpu at least from
> > its
> > hard affinity, what is it exactly that you are not understanding?
> If I put it simply ,  can  (X being a vcpu)
> x {soft affinity pcpus} Intersect x { hard affinity pcpu} -> be Null
> or 
> disjoint set ?
> and
> 
The user can setup things such that:

 soft-affinity{X} intersection hard-affinity{X} = O

but this, here inside the scheduler, is considered like X does not have
any soft-affinity at all, i.e., only X's hard-affinity is considered,
and all the balancing steps and operations and consideration related to
soft-affinity are ignored/skipped.

That's because it's absolutely pointless to try figure out where to
execute X, among the set of the pCPUs it prefers to run on, if it
_can't_ actually run on any pCPU from that same set.

So the answer to your question is: "it seems to be possible for the
intersection to be void, but in practise, it is not." :-)

> x{runnable pcpu} intersect (x{hard affinity pcpu} union x{soft
> affinity 
> pcpu} ) -> be null or disjoint ??
> 
I still don't get this. In particular, I'm not sure what
'x{runnable pcpu}' is. Also the union of a vcpu's soft and hard
affinity is never done (it's, as explained above, the intersection that
counts).

Regards,
Dario
-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


[-- Attachment #1.2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

[-- Attachment #2: Type: text/plain, Size: 127 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel

  reply	other threads:[~2016-09-07 13:32 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-17 17:17 [PATCH 00/24] sched: Credit1 and Credit2 improvements... and soft-affinity for Credit2! Dario Faggioli
2016-08-17 17:17 ` [PATCH 01/24] xen: credit1: small optimization in Credit1's tickling logic Dario Faggioli
2016-09-12 15:01   ` George Dunlap
2016-08-17 17:17 ` [PATCH 02/24] xen: credit1: fix mask to be used for tickling in Credit1 Dario Faggioli
2016-08-17 23:42   ` Dario Faggioli
2016-09-12 15:04     ` George Dunlap
2016-08-17 17:17 ` [PATCH 03/24] xen: credit1: return the 'time remaining to the limit' as next timeslice Dario Faggioli
2016-09-12 15:14   ` George Dunlap
2016-09-12 17:00     ` Dario Faggioli
2016-09-14  9:34       ` George Dunlap
2016-09-14 13:54         ` Dario Faggioli
2016-08-17 17:18 ` [PATCH 04/24] xen: credit2: properly schedule migration of a running vcpu Dario Faggioli
2016-09-12 17:11   ` George Dunlap
2016-08-17 17:18 ` [PATCH 05/24] xen: credit2: make tickling more deterministic Dario Faggioli
2016-08-31 17:10   ` anshul makkar
2016-09-05 13:47     ` Dario Faggioli
2016-09-07 12:25       ` anshul makkar
2016-09-13 11:13       ` George Dunlap
2016-09-29 15:24         ` Dario Faggioli
2016-09-13 11:28   ` George Dunlap
2016-09-30  2:22     ` Dario Faggioli
2016-08-17 17:18 ` [PATCH 06/24] xen: credit2: implement yield() Dario Faggioli
2016-09-13 13:33   ` George Dunlap
2016-09-29 16:05     ` Dario Faggioli
2016-09-20 13:25   ` George Dunlap
2016-09-20 13:37     ` George Dunlap
2016-08-17 17:18 ` [PATCH 07/24] xen: sched: don't rate limit context switches in case of yields Dario Faggioli
2016-09-20 13:32   ` George Dunlap
2016-09-29 16:46     ` Dario Faggioli
2016-08-17 17:18 ` [PATCH 08/24] xen: tracing: add trace records for schedule and rate-limiting Dario Faggioli
2016-08-18  0:57   ` Meng Xu
2016-08-18  9:41     ` Dario Faggioli
2016-09-20 13:50   ` George Dunlap
2016-08-17 17:18 ` [PATCH 09/24] xen/tools: tracing: improve tracing of context switches Dario Faggioli
2016-09-20 14:08   ` George Dunlap
2016-08-17 17:18 ` [PATCH 10/24] xen: tracing: improve Credit2's tickle_check and burn_credits records Dario Faggioli
2016-09-20 14:35   ` George Dunlap
2016-09-29 17:23     ` Dario Faggioli
2016-09-29 17:28       ` George Dunlap
2016-09-29 20:53         ` Dario Faggioli
2016-08-17 17:18 ` [PATCH 11/24] tools: tracing: handle more scheduling related events Dario Faggioli
2016-09-20 14:37   ` George Dunlap
2016-08-17 17:18 ` [PATCH 12/24] xen: libxc: allow to set the ratelimit value online Dario Faggioli
2016-09-20 14:43   ` George Dunlap
2016-09-20 14:45     ` Wei Liu
2016-09-28 15:44   ` George Dunlap
2016-08-17 17:19 ` [PATCH 13/24] libxc: improve error handling of xc Credit1 and Credit2 helpers Dario Faggioli
2016-09-20 15:10   ` Wei Liu
2016-08-17 17:19 ` [PATCH 14/24] libxl: allow to set the ratelimit value online for Credit2 Dario Faggioli
2016-08-22  9:21   ` Ian Jackson
2016-09-05 14:02     ` Dario Faggioli
2016-08-22  9:28   ` Ian Jackson
2016-09-28 15:37     ` George Dunlap
2016-09-30  1:03     ` Dario Faggioli
2016-09-28 15:39   ` George Dunlap
2016-08-17 17:19 ` [PATCH 15/24] xl: " Dario Faggioli
2016-09-28 15:46   ` George Dunlap
2016-08-17 17:19 ` [PATCH 16/24] xen: sched: factor affinity helpers out of sched_credit.c Dario Faggioli
2016-09-28 15:49   ` George Dunlap
2016-08-17 17:19 ` [PATCH 17/24] xen: credit2: soft-affinity awareness in runq_tickle() Dario Faggioli
2016-09-01 10:52   ` anshul makkar
2016-09-05 14:55     ` Dario Faggioli
2016-09-07 13:24       ` anshul makkar
2016-09-07 13:31         ` Dario Faggioli [this message]
2016-09-28 20:44   ` George Dunlap
2016-08-17 17:19 ` [PATCH 18/24] xen: credit2: soft-affinity awareness fallback_cpu() and cpu_pick() Dario Faggioli
2016-09-01 11:08   ` anshul makkar
2016-09-05 13:26     ` Dario Faggioli
2016-09-07 12:52       ` anshul makkar
2016-09-29 11:11   ` George Dunlap
2016-08-17 17:19 ` [PATCH 19/24] xen: credit2: soft-affinity awareness in load balancing Dario Faggioli
2016-09-02 11:46   ` anshul makkar
2016-09-05 12:49     ` Dario Faggioli
2016-08-17 17:19 ` [PATCH 20/24] xen: credit2: kick away vcpus not running within their soft-affinity Dario Faggioli
2016-08-17 17:20 ` [PATCH 21/24] xen: credit2: optimize runq_candidate() a little bit Dario Faggioli
2016-08-17 17:20 ` [PATCH 22/24] xen: credit2: "relax" CSCHED2_MAX_TIMER Dario Faggioli
2016-09-30 15:30   ` George Dunlap
2016-08-17 17:20 ` [PATCH 23/24] xen: credit2: optimize runq_tickle() a little bit Dario Faggioli
2016-09-02 12:38   ` anshul makkar
2016-09-05 12:52     ` Dario Faggioli
2016-08-17 17:20 ` [PATCH 24/24] xen: credit2: try to avoid tickling cpus subject to ratelimiting Dario Faggioli
2016-08-18  0:11 ` [PATCH 00/24] sched: Credit1 and Credit2 improvements... and soft-affinity for Credit2! Dario Faggioli
2016-08-18 11:49 ` Dario Faggioli
2016-08-18 11:53 ` Dario Faggioli

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1473255104.19612.125.camel@citrix.com \
    --to=dario.faggioli@citrix.com \
    --cc=anshul.makkar@citrix.com \
    --cc=george.dunlap@citrix.com \
    --cc=jtweaver@hawaii.edu \
    --cc=xen-devel@lists.xenproject.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.