Hi,
On 09/04/2018 09:49 AM, Jan Beulich wrote:
On 04.09.18 at 09:38, <jgr...@suse.com> wrote:
On 03/09/18 15:41, Jan Beulich wrote:
On 31.08.18 at 17:22, <jgr...@suse.com> wrote:
The topology information obtainable via XEN_SYSCTL_cputopoinfo is
filled rather weird: the size of the array is derived from the highest
online cpu number, so in case there are trailing offline cpus they
will not be included.
On a dual core system with 4 threads booted with smt=0 without this
patch xl info -n will print:
cpu_topology :
cpu: core socket node
0: 0 0 0
1: 0 0 0
2: 1 0 0
while with this patch the output is:
cpu_topology :
cpu: core socket node
0: 0 0 0
1: 0 0 0
2: 1 0 0
3: 1 0 0
Signed-off-by: Juergen Gross <jgr...@suse.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com>
for x86. I'd like this to have an ARM ack as well, though, for
there possibly being differences in how cpu_present_map is
handled in their case. In particular I notice that the only access
to the variable is in smp_prepare_cpus().
How relevant is that information for arm at all?
cpu_to_core(i) et al always return 0. So topology information is not
really helpful.
Well, this is common code and at some point we will read the CPU
topology to improve scheduling. This has not been done so far because
there are other important part to focus first.
Stefano, Julien?
I think the patch makes sense for Arm too:
Acked-by: Julien Grall <julien.gr...@arm.com>
At the moment, cpu_present_map is a copy of cpu_online_map. I would
expect this to change when hotplug will be supported.
Cheers,
--
Julien Grall
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