From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Zhigang Wang <zhigang.x.wang@oracle.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
Ian Jackson <Ian.Jackson@eu.citrix.com>
Subject: Re: xl: expose max_cpu_id from `xl info`
Date: Wed, 14 Mar 2012 10:45:37 +0000 [thread overview]
Message-ID: <4F6076D1.3000804@citrix.com> (raw)
In-Reply-To: <4F5F9CCF.9000400@oracle.com>
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On 13/03/12 19:15, Zhigang Wang wrote:
> On 03/13/2012 12:52 PM, Andrew Cooper wrote:
>> This will allow userspace to reason with the total number of CPUs, not
>> just the current number of online CPUs.
>>
>> -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44
>> (0)1223 225 900, http://www.citrix.com
>>
>> xl-info-max_cpu_id.patch
>>
>>
>> # HG changeset patch
>> # Parent 5d20d2f6ffed0a49f030f04a8870f1926babbcbf
>> xl: display max_cpu_ids for xl info
>>
>> Expose "max_cpu_id" in stdout from `xl info`
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>>
>> diff -r 5d20d2f6ffed tools/libxl/xl_cmdimpl.c
>> --- a/tools/libxl/xl_cmdimpl.c
>> +++ b/tools/libxl/xl_cmdimpl.c
>> @@ -3734,6 +3734,7 @@ static void output_physinfo(void)
>> }
>>
>> printf("nr_cpus : %d\n", info.nr_cpus);
>> + printf("max_cpu_id : %d\n", info.max_cpu_id);
>
> Is this true: nr_cpus = max_cpu_id + 1 ?
>
> Zhigang
if and only if all cpus are online.
nr_cpus is set to nr_online_cpus() in the hypercall, while max_cpu_id is
set to nr_cpu_ids-1.
nr_cpus is liable to change during runtime, while max_cpu_id is not.
~Andrew
>
>> printf("nr_nodes : %d\n", info.nr_nodes);
>> printf("cores_per_socket : %d\n", info.cores_per_socket);
>> printf("threads_per_core : %d\n", info.threads_per_core);
>>
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xen.org
>> http://lists.xen.org/xen-devel
>
--
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com
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next prev parent reply other threads:[~2012-03-14 10:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-13 16:52 xl: expose max_cpu_id from `xl info` Andrew Cooper
2012-03-13 19:15 ` Zhigang Wang
2012-03-14 10:45 ` Andrew Cooper [this message]
2012-03-14 15:48 ` Zhigang Wang
2012-03-14 16:24 ` Andrew Cooper
2012-03-14 17:51 ` Zhigang Wang
2012-03-14 11:10 ` Ian Jackson
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