[Crash-utility] [PATCH RFC 0/1] Display relative lag of each CPU

[Oleksandr Natalenko]

Hi, Dave.

The question about indentation for column output is whether you prefer
simple tabulation ("\t"), or calculated amount of spaces. Tabs are
simpler, but in case we have big CPU number, output may be shifted.

This is the only concern from me regarding this submission.

On Wed, Nov 8, 2017 at 5:33 PM, Dave Anderson <anderson at redhat.com> wrote:
>
>
> ----- Original Message -----
>> While analyzing vmcore it is useful to have an information
>> about relative lag of each CPU. Usually, people do something like this:
>>
>> runq -t | grep CPU | sort -k3r |
>>   awk 'NR==1{now=strtonum("0x"$3)}1{printf"%s\t%7.2fs behind\n",
>>        $0,(now-strtonum("0x"$3))/1000000000}'
>>
>> Here, most recent runqueue timestamp is taken as a basis, and other
>> runqueues are assumed to lag behind it. This information can tell
>> the reviewer which CPU is experiencing some lockup, which is
>> especially useful for vmcores taken in virtual machines.
>>
>> I think it would be nice to have this feature implemented by crash
>> utility itself.
>
> OK...
>
>> Since this is an RFC and if this enhancement looks useful, I'd like
>> to ask to assist me with output indentation since dump_on_rq_timestamp(),
>> for instance, looks too implicit and (honestly) awful to use as it is.
>
> I don't know what you need assistance for?
>
> Dave
>
>
>> Oleksandr Natalenko (1):
>>   runq: display relative lag of each CPU
>>
>>  help.c |  4 +++-
>>  task.c | 76
>>  +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>>  2 files changed, 78 insertions(+), 2 deletions(-)
>>
>> --
>> 2.15.0
>>
>>



-- 
Best regards,
  Oleksandr Natalenko (post-factum)
  Software Maintenance Engineer