[LTP] [PATCH] cpu_hotplug/cpuhotplug03.sh: Accurately select command name by -C option

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

Hi Petr,

Could you push this patch if nobody has objections. :-)

Best Regards,
Xiao Yang
On 2018/12/06 5:13, Petr Vorel wrote:
> Hi Xiao,
>
>> Since procps v3.3.15, running cpuhotplug03.sh got the following error:
>> ----------------------------------------------------------------------
>> cpuhotplug03 1 TINFO: Onlining CPU 1
>> cpuhotplug03 1 TBROK: No cpuhotplug_do_spin_loop processes found on any processor
>> ----------------------------------------------------------------------
>> On procps v3.3.15, ps command name selection is extended to 64 characters
>> so procps cannot trucate normal command name to 15 characters by default.
>> In addition, normal command name is truncated to 16 characters and stored
>> in /proc/<pid>/stat and /proc/<pid>/status in kernel.(except workqueue worker
>> because it has been extended to 64 by kernel commit 6b59808)
>> References:
>> procps commit: bb272580a6f3c192c61e307f9e341514d892d06e
>> procps commit: 14005a371e5c14289e96a4927ffd1a827d3c9d85
>> procps commit: 2cfdbbe897f0d4e41460c7c2b92acfc5804652c8
>> kernel commit: 6b59808bfe482642287ddf3fe9d4cccb10756652
>> Note:
>> I think the lastest ps(1) manpage for command name length is confused
>> because kernel only extend workqueue worker name to 64 characters by
>> commit 6b59808 and still truncate normal command name to 16 characters.
>> e.g:
>> ---------------------------------------------------------------------
>> cd /root/ltp/testcases/kernel/hotplug/cpu_hotplug/tools
>> PATH=$PATH:$PWD cpuhotplug_do_spin_loop&
>> [1] 8732
>> cat /proc/8732/stat
>> 8732 (cpuhotplug_do_s) ...
>> cat /proc/8732/status | grep Name
>> Name:   cpuhotplug_do_s
>> ---------------------------------------------------------------------
> Agree.
>
>> I will try to update ps(1) manpage for command name length.
> Good :).
>
>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
> Acked-by: Petr Vorel<pvorel@suse.cz>
>> ---
>>   .../kernel/hotplug/cpu_hotplug/functional/cpuhotplug03.sh    | 12 ++++++++++--
>>   1 file changed, 10 insertions(+), 2 deletions(-)
>
> Kind regards,
> Petr
>
>
> .
>