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

[Oleksandr Natalenko]

OK, I'll check this and post v2.

Thanks.

On Thu, Nov 9, 2017 at 3:14 PM, Dave Anderson <anderson at redhat.com> wrote:
>
>
> ----- Original Message -----
>> 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.
>
> Tabs aren't used in any crash command output, so preferably it would use
> a calculated number of leading spaces, typically a minimum of 2 shifted
> right depending upon the number of cpus, so that the colons line up:
>
>    CPU 9:
>   CPU 10:
>
> Thanks,
>   Dave
>
>>
>> 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
>>



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