From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Ernast Sevo <ersevs@gmail.com>
Cc: Wolfgang Grandegger <wg@grandegger.com>,
"linux-can@vger.kernel.org" <linux-can@vger.kernel.org>
Subject: Re: command ip -details -statistics link show wlan0
Date: Thu, 16 May 2013 17:37:53 +0200 [thread overview]
Message-ID: <5194FD51.1030803@pengutronix.de> (raw)
In-Reply-To: <CAOD0pena8JLpCsq6EUqqy_Rip0oRe0Z5=6SQfGV2TNeS_YABfQ@mail.gmail.com>
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On 05/16/2013 05:32 PM, Ernast Sevo wrote:
>> Well, not sure if the hardware realizes any packet lost. This typically
>> happens when the software does not empty the hardware buffers quickly
>> enough? What hardware are you using? MCP251x?
> Yes I am using MCP2515. I am getting a couple of rx buffer overflow errors
> so I was wondering how these errors corresponded to packet loss,
> whether this is a 1:1 relationship or 1:N relationship (if i am
> interpretting Marc's post
> correctly should I assume 1:1 for best case and 1:N for worst case? ).
Yes, exactly.
> Essentially I am trying to determine at what speed i can have stuff
> coming in before
> I start losing packets for any reason. I know how to account packets
> lost in userspace
> and packets lost by the driver (which you mentioned above) and now I
> am trying to
> account for packets lost at the hardware level. Knowing how these rx buffer
> overflow/overrun errors correspond to packet loss would help make my
> data more accurate and reliable.
If you don't get any dropped frames reported via SO_RXQ_OVFL (see
Wolfgang mail) you can be sure they are lost at the hardware level. I
suggest don't use the mcp251x, it's really slow and puts heavy load on
the machine. However there might be some knobs to tune in your SPI
controller/driver.
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
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next prev parent reply other threads:[~2013-05-16 15:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-15 18:58 command ip -details -statistics link show wlan0 Ernast Sevo
2013-05-16 7:02 ` Wolfgang Grandegger
[not found] ` <CAOD0pekopW9g0SD=BnOMCEp3SdVZPrx5jY_CKLjZV09sWepS6A@mail.gmail.com>
2013-05-16 13:43 ` Ernast Sevo
2013-05-16 13:45 ` Marc Kleine-Budde
[not found] ` <5194F46D.4060905@grandegger.com>
2013-05-16 15:32 ` Ernast Sevo
2013-05-16 15:37 ` Marc Kleine-Budde [this message]
2013-05-16 15:43 ` Wolfgang Grandegger
2013-05-16 16:37 ` Ernast Sevo
[not found] ` <CAOD0pekym7Ey1eRn-ndwjEnsJUpf84xHbexztpRBjUKqoaGcPw@mail.gmail.com>
[not found] ` <51B239EA.6060603@grandegger.com>
2013-06-08 7:42 ` Wolfgang Grandegger
2013-06-10 12:53 ` Ernast Sevo
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