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From: Sergey Dyasli <sergey.dyasli@citrix.com>
To: Juergen Gross <jgross@suse.com>
Cc: Sergey Dyasli <sergey.dyasli@citrix.com>, Wei Liu <wl@xen.org>,
	Andrew Cooper <Andrew.Cooper3@citrix.com>,
	George Dunlap <George.Dunlap@citrix.com>,
	Dario Faggioli <dfaggioli@suse.com>,
	Jan Beulich <jbeulich@suse.com>,
	"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
	Ian Jackson <Ian.Jackson@citrix.com>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: [Xen-devel] xl vcpu-pin peculiarities in core scheduling mode
Date: Tue, 24 Mar 2020 13:34:15 +0000	[thread overview]
Message-ID: <1585056853121.58010@citrix.com> (raw)

Hi Juergen,

I've notived there is no documentation about how vcpu-pin is supposed to work
with core scheduling enabled. I did some experiments and noticed the following
inconsistencies:

  1. xl vcpu-pin 5 0 0
     Windows 10 (64-bit) (1)              5     0    0   -b-    1644.0  0 / all
     Windows 10 (64-bit) (1)              5     1    1   -b-    1650.1  0 / all
                                                     ^                  ^
     CPU 1 doesn't match reported hard-affinity of 0. Should this command set
     hard-affinity of vCPU 1 to 1? Or should it be 0-1 for both vCPUs instead?


  2. xl vcpu-pin 5 0 1
     libxl: error: libxl_sched.c:62:libxl__set_vcpuaffinity: Domain 5:Setting vcpu affinity: Invalid argument
     This is expected but perhaps needs documenting somewhere?


  3. xl vcpu-pin 5 0 1-2
     Windows 10 (64-bit) (1)              5     0    2   -b-    1646.7  1-2 / all
     Windows 10 (64-bit) (1)              5     1    3   -b-    1651.6  1-2 / all
                                                     ^                  ^^^
     Here is a CPU / affinity mismatch again, but the more interesting fact
     is that setting 1-2 is allowed at all, I'd expect CPU would never be set
     to 1 with such settings.

Please let me know what you think about the above cases.

--
Thanks,
Sergey


             reply	other threads:[~2020-03-24 13:34 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-24 13:34 Sergey Dyasli [this message]
2020-03-24 14:22 ` [Xen-devel] xl vcpu-pin peculiarities in core scheduling mode Jürgen Groß
2020-03-24 14:55   ` Dario Faggioli

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