From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: xl: expose max_cpu_id from `xl info` Date: Wed, 14 Mar 2012 10:45:37 +0000 Message-ID: <4F6076D1.3000804@citrix.com> References: <4F5F7B49.9040001@citrix.com> <4F5F9CCF.9000400@oracle.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============3200279690733700096==" Return-path: In-Reply-To: <4F5F9CCF.9000400@oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Zhigang Wang Cc: "xen-devel@lists.xensource.com" , Ian Jackson List-Id: xen-devel@lists.xenproject.org --===============3200279690733700096== Content-Type: multipart/alternative; boundary="------------020109030901030505060903" --------------020109030901030505060903 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit 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 >> >> 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 --------------020109030901030505060903 Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit 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);



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-- 
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com
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