From: David Laight <David.Laight@ACULAB.COM>
To: 'Richard Weinberger' <richard@nod.at>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Cc: "wei.fang@nxp.com" <wei.fang@nxp.com>,
"shenwei.wang@nxp.com" <shenwei.wang@nxp.com>,
"xiaoning.wang@nxp.com" <xiaoning.wang@nxp.com>,
"linux-imx@nxp.com" <linux-imx@nxp.com>
Subject: RE: high latency with imx8mm compared to imx6q
Date: Fri, 17 Feb 2023 20:49:23 +0000 [thread overview]
Message-ID: <b4fc00958e0249208b5aceecfa527161@AcuMS.aculab.com> (raw)
In-Reply-To: <1422776754.146013.1676652774408.JavaMail.zimbra@nod.at>
From: Richard Weinberger
> Sent: 17 February 2023 16:53
...
> I'm investigating into latency issues on an imx8mm system after
> migrating from imx6q.
> A regression test showed massive latency increases when single/small packets
> are exchanged.
>
> A simple test using ping exhibits the problem.
> Pinging the very same host from the imx8mm has a way higher RTT than from the imx6.
>
> Ping, 100 packets each, from imx6q:
> rtt min/avg/max/mdev = 0.689/0.851/1.027/0.088 ms
>
> Ping, 100 packets each, from imx8mm:
> rtt min/avg/max/mdev = 1.073/2.064/2.189/0.330 ms
>
> You can see that the average RTT has more than doubled.
...
Is it just interrupt latency caused by interrupt coalescing
to avoid excessive interrupts?
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2023-02-17 20:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-17 16:52 fec: high latency with imx8mm compared to imx6q Richard Weinberger
2023-02-17 20:49 ` David Laight [this message]
2023-02-18 1:04 ` Andrew Lunn
2023-02-18 1:27 ` Wei Fang
2023-02-18 9:42 ` Richard Weinberger
2023-02-18 11:52 ` Wei Fang
2023-02-18 12:03 ` Richard Weinberger
2023-02-18 12:28 ` Wei Fang
2023-02-18 12:29 ` Wei Fang
2023-02-18 13:20 ` Richard Weinberger
2023-02-20 0:11 ` Andrew Lunn
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