From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: Philip Ha <philwman@domain.hid>
Cc: Xenomai-help@domain.hid
Subject: Re: [Xenomai-help] clock problem
Date: Fri, 05 Aug 2011 14:53:11 +0200 [thread overview]
Message-ID: <4E3BE7B7.3040505@domain.hid> (raw)
In-Reply-To: <1312486056.62780.YahooMailClassic@domain.hid>
On 08/04/2011 09:27 PM, Philip Ha wrote:
>> Would it be possible for you to send mails formatted correctly?
>>
>> Then the bug is somewhere in between the serial line and the test
>> application, including possibly in the driver.
>>
>> In order to know where it is, you should compute the latency at each
>> point on this path: when receiving the interrupt, when waking up the
>> task, etc...
>
> Hi Gilles,
>
> Sorry for the formatting, I am new to mailing lists.
>
> I have looked at the latency in the 16550A driver. The first thing
> the driver does in its ISR is to call rtdm_clock_read and store the
> resulting timestamp in a "struct rtser_event". The code I posted
> grabs this structure. If I use this as my timestamp I get the exact
> same timing results.
are you sure that the interrupt triggers as soon as you receive a
character, and not upon timeout when not receiving characters for some
time? After all, 100us is approximately the time to transmit one
character at 115200 bauds on the serial line.
--
Gilles.
next prev parent reply other threads:[~2011-08-05 12:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-04 19:27 [Xenomai-help] clock problem Philip Ha
2011-08-05 12:53 ` Gilles Chanteperdrix [this message]
2011-08-08 16:44 ` Philip Ha
2011-08-08 18:00 ` Gilles Chanteperdrix
-- strict thread matches above, loose matches on Subject: below --
2011-08-15 13:50 Philip Ha
2011-08-11 21:18 Philip Ha
2011-08-11 22:24 ` Gilles Chanteperdrix
2011-08-10 15:18 Philip Ha
2011-08-10 15:49 ` Gilles Chanteperdrix
2011-08-04 15:55 Philip Ha
2011-08-04 16:39 ` Gilles Chanteperdrix
2011-08-04 17:26 ` Philip Ha
2011-08-04 17:34 ` Gilles Chanteperdrix
[not found] <1311873701.2537.YahooMailClassic@domain.hid>
2011-07-31 17:19 ` Gilles Chanteperdrix
[not found] <1311805213.7716.YahooMailClassic@domain.hid>
2011-07-28 14:35 ` Gilles Chanteperdrix
2011-07-20 18:35 Philip Ha
2011-07-19 14:24 Philip Ha
2011-07-27 18:47 ` Gilles Chanteperdrix
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