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From: George Dunlap <george.dunlap@citrix.com>
To: Andrii Anisov <andrii_anisov@epam.com>,
	Andrii Anisov <andrii.anisov@gmail.com>,
	xen-devel@lists.xen.org
Cc: George Dunlap <george.dunlap@eu.citrix.com>,
	Wei Liu <wei.liu2@citrix.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	Dario Faggioli <dfaggioli@suse.com>
Subject: Re: [PATCH 1/5] xentrace_format: print timestamps in nanoseconds
Date: Tue, 11 Sep 2018 11:44:26 +0100	[thread overview]
Message-ID: <2fa12bbc-ace0-c75e-96bd-431cb4d49158@citrix.com> (raw)
In-Reply-To: <732445b5-59cf-5416-455d-f994ee2aa47c@epam.com>

On 09/11/2018 11:32 AM, Andrii Anisov wrote:
> Hello George,
> 
> 
> On 11.09.18 13:15, George Dunlap wrote:
>>>           if mhz:
>>> -            tsc = tsc / (mhz*1000000.0)
>>> +            tsc = tsc * 1000.0 / mhz
>> Why do you prefer this?
> I'm playing with scheduling from one hand, so time stamps in seconds
> does not give understanding about what's going on.
> From other hand I'm quite confused about how useful timestamps in
> seconds could be for traces. As per my understanding, tracer should be
> useful for debugging some rapidly changing processes.

Oh, sorry -- I missed the point of this patch.

---
xentrace_format: print timestamps in nanoseconds

...rather than seconds.  Having timestamps for rapidly-occurring events
in nanoseconds makes it easier to understand what's going on.

While here, document the -c option.
---

What I do in xenalyze is to have the timestamps in seconds, but always
print down to the nanosecond.  (For this I actually break cpu cycles
into s and ns separately, and then print "%u.%09u".)

But this is also fine with me.

 -George

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  reply	other threads:[~2018-09-11 10:44 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-10 16:41 [PATCH 0/5] Misc changes to xentrace_format Andrii Anisov
2018-09-10 16:41 ` [PATCH 1/5] xentrace_format: print timestamps in nanoseconds Andrii Anisov
2018-09-11 10:15   ` George Dunlap
2018-09-11 10:32     ` Andrii Anisov
2018-09-11 10:44       ` George Dunlap [this message]
2018-09-11 10:45         ` George Dunlap
2018-09-11 15:19         ` Andrii Anisov
2018-09-11 15:54           ` George Dunlap
2018-09-12  7:42             ` Dario Faggioli
2018-09-12 16:44               ` Andrii Anisov
2018-09-12 17:16             ` Andrii Anisov
2018-09-10 16:41 ` [PATCH 2/5] xentrace_format: switch mhz option to float Andrii Anisov
2018-09-11 10:21   ` George Dunlap
2018-09-10 16:41 ` [PATCH 3/5] xentrace_format: combine 64-bit LE values from traces Andrii Anisov
2018-09-11 10:48   ` George Dunlap
2018-09-11 12:23     ` Andrii Anisov
2018-09-12  7:47       ` Dario Faggioli
2018-09-10 16:41 ` [PATCH 4/5] formats: allign trace record format to the current code Andrii Anisov
2018-09-11 10:51   ` George Dunlap
2018-09-12  7:49   ` Dario Faggioli
2018-09-10 16:41 ` [PATCH 5/5] formats: print time values as decimals Andrii Anisov
2018-09-11 10:33   ` George Dunlap
2018-09-12  7:54     ` Dario Faggioli
2018-09-12 17:28       ` Andrii Anisov
2018-09-12 17:43         ` Dario Faggioli

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