[Crash-utility] FW: Number of cpus on ARM

[Dave Anderson]

----- Original Message -----
> 
> Hello
> 
> That would be a possibility but I prefer if crash can calculate the correct
> number of cpus itself.
>
 
Right, the --cpus option is only there as a workaround.

> If we just want to set the number of cpus to the number of cpus present, then
> the function “get_cpus_present()” could probably be used.

I prefer your patch copying ARM64.  You could throw get_cpus_present() in there,
but it wouldn't apply to 2.6.29 and earlier kernels.

Dave
 
> 
> 
> Jan
> 
> 
> 
> Jan Karlsson
> 
> Senior Software Engineer
> 
> System Assurance
> 
> 
> 
> Sony Mobile Communications
> 
> Tel: +46 703 062 174
> 
> jan.karlsson at sonymobile.com
> 
> 
> 
> sonymobile.com
> 
> 
> 
> 
> 
> 
> 
> 
> From: crash-utility-bounces at redhat.com
> [mailto:crash-utility-bounces at redhat.com] On Behalf Of Arun KS
> Sent: den 15 oktober 2014 11:57
> To: Discussion list for crash utility usage, maintenance and development
> Subject: Re: [Crash-utility] FW: Number of cpus on ARM
> 
> 
> 
> 
> 
> Hello Jan,
> 
> 
> 
> 
> 
> Can you try with option --cpus=4 passed when your start the crash.
> 
> 
> I used 4 here because i have 4 cores.
> 
> 
> 
> 
> 
> Thanks,
> 
> 
> Arun
> 
> 
> 
> 
> 
> On Wed, Oct 15, 2014 at 2:49 PM, Karlsson, Jan < Jan.Karlsson at sonymobile.com
> > wrote:
> 
> 
> Hi
> 
> 
> 
> Unfortunately I found another older example where my patch below did not
> work.
> 
> In that one only cpu 0 where online but 0,1,2,3 where active. So maybe:
> 
> 
> 
> return MAX(get_cpus_active(), get_highest_cpu_online()+1);
> 
> 
> 
> might work better. Someone with better knowledge about this than I have
> should look at the problem.
> 
> 
> 
> Jan
> 
> 
> 
> 
> Jan Karlsson
> 
> Senior Software Engineer
> 
> System Assurance
> 
> 
> 
> Sony Mobile Communications
> 
> Tel: +46 703 062 174
> 
> jan.karlsson at sonymobile.com
> 
> 
> 
> sonymobile.com
> 
> 
> 
> 
> 
> 
> 
> 
> 
> From: Karlsson, Jan
> Sent: den 15 oktober 2014 10:49
> To: Discussion list for crash utility usage, maintenance and development
> Subject:
> 
> 
> 
> 
> Hi
> 
> 
> 
> I have seen a problem when it comes to the number of cpus for ARM (32-bits).
> 
> 
> 
> static int
> 
> arm_get_smp_cpus(void)
> 
> {
> 
> return MAX(get_cpus_active(), get_cpus_online());
> 
> }
> 
> 
> 
> In one of my example, “help –k” gives me:
> 
> cpu_possible_map: 0 1 2 3
> 
> cpu_present_map: 0 1 2 3
> 
> cpu_online_map: 0 3
> 
> cpu_active_map: 3
> 
> 
> 
> So the number of cpus will become 2. However there are code in a number of
> places that will then only accept cpu 0 and 1 as cpus to handle.
> 
> 
> 
> When I changed to code to be the same as for ARM64 things worked as expected:
> 
> 
> 
> static int
> 
> arm_get_smp_cpus(void)
> 
> {
> 
> return MAX(get_cpus_online(), get_highest_cpu_online()+1);
> 
> }
> 
> 
> 
> Jan
> 
> 
> 
> Jan Karlsson
> 
> Senior Software Engineer
> 
> System Assurance
> 
> 
> 
> Sony Mobile Communications
> 
> Tel: +46 703 062 174
> 
> jan.karlsson at sonymobile.com
> 
> 
> 
> sonymobile.com
> 
> 
> 
> 
> 
> 
> 
> 
> 
> --
> Crash-utility mailing list
> Crash-utility at redhat.com
> https://www.redhat.com/mailman/listinfo/crash-utility
> 
> 
> 
> 
> --
> Crash-utility mailing list
> Crash-utility at redhat.com
> https://www.redhat.com/mailman/listinfo/crash-utility