Re: [PATCH v5 5/5] xen/console: Traditional console timestamps including milliseconds

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 11/03/14 13:54, Ian Campbell wrote:
> On Tue, 2014-03-11 at 11:08 +0000, Andrew Cooper wrote:
>> On 11/03/14 11:06, David Vrabel wrote:
>>> On 11/03/14 10:55, Andrew Cooper wrote:
>>>> On 11/03/14 10:13, Ian Campbell wrote:
>>>>> On Fri, 2014-03-07 at 17:28 +0000, Andrew Cooper wrote:
>>>>>> Suggested-by: Don Slutz <dslutz@verizon.com>
>>>>>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>>>>>> CC: Keir Fraser <keir@xen.org>
>>>>>> CC: Jan Beulich <JBeulich@suse.com>
>>>>>> CC: Ian Campbell <ian.campbell@citrix.com>
>>>>>> CC: Stefano Stabellini <stefano.stabellini@citrix.com>
>>>>>> CC: Tim Deegan <tim@xen.org>
>>>>>>
>>>>>> ---
>>>>>>
>>>>>> The change in arm is only for the sake of compilation - the function is a
>>>>>> no-op.
>>>>> Acked-by: Ian Campbell <ian.campbell@citrix.com>
>>>>>
>>>>>> v5: Correct check for null in wallclock_time()
>>>>>> ---
>>>>>>  docs/misc/xen-command-line.markdown |    4 +++-
>>>>>>  xen/arch/arm/time.c                 |    2 +-
>>>>>>  xen/arch/x86/time.c                 |   10 +++++++---
>>>>>>  xen/drivers/char/console.c          |   11 ++++++++++-
>>>>>>  xen/include/xen/time.h              |    2 +-
>>>>>>  5 files changed, 22 insertions(+), 7 deletions(-)
>>>>>>
>>>>>> diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
>>>>>> index e437091..ced5eca 100644
>>>>>> --- a/docs/misc/xen-command-line.markdown
>>>>>> +++ b/docs/misc/xen-command-line.markdown
>>>>>> @@ -275,7 +275,7 @@ cleared.  This allows a single port to be shared by two subsystems
>>>>>>  makes sense on its own.
>>>>>>  
>>>>>>  ### console\_timestamps
>>>>>> -> `= none | date | boot`
>>>>>> +> `= none | date | datems | boot`
>>>>> I think someone (David V?) asked this earlier but I don't remember a
>>>>> response: Why do we need to support multiple timestamp formats? Can't we
>>>>> just pick one which has reasonable accuracy/information content and
>>>>> stick with it?
>>>>>
>>>>> Ian.
>>>>>
>>>> That is posed as an RFC in patch 0, which has gone without comment for
>>>> several versions of this series now.
>>>>
>>>> XenServer has timestamps enabled by default, and in my opinion is too
>>>> long (space wise) and insufficiently precise.  That is why I introduced
>>>> the linux-style timestamps.
>>>>
>>>> Don has expressed interest in keeping the existing format, preferring it
>>>> to linux-style.
> Did he say why? (sorry, I'm catching up on mail backlog, so maybe I
> missed this.

Yes, the same as Sander hooked off this thread.  To match entries in the
Xen console with other log files.

This patch is Suggested-by: Don, given the previous dicussions

>
> Are there examples of the various formats somewhere?

In the patched markdown for patches 4 and 5, as well as in the enum
TSM_* from the same two patches.

>
>>   Furthermore, the precision issue has been addressed, at
>>>> the expense of extra length, space wise.
>>> Wallclock date/time timestamps may be better served by a klogd like
>>> logging daemon in dom0 (but such a daemon doesn't exist yet).
>>>
>>> David
>> Not if you want timestamps on the serial console,
> At least around here the serial console server takes care of that most
> of the time.
>
> Ian.

If you are purely logging them, but not if you are working on the serial
console itself, which is what I find myself doing for a surprisingly
large amount of my work.

~Andrew