From: Andrew Lunn <andrew@lunn.ch>
To: Gerhard Engleder <gerhard@engleder-embedded.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org,
edumazet@google.com, pabeni@redhat.com
Subject: Re: [PATCH net-next 1/4] tsnep: Throttle interrupts
Date: Thu, 17 Nov 2022 21:33:56 +0100 [thread overview]
Message-ID: <Y3aatP+384keCkpN@lunn.ch> (raw)
In-Reply-To: <20221117201440.21183-2-gerhard@engleder-embedded.com>
On Thu, Nov 17, 2022 at 09:14:37PM +0100, Gerhard Engleder wrote:
> Without interrupt throttling, iperf server mode generates a CPU load of
> 100% (A53 1.2GHz). Also the throughput suffers with less than 900Mbit/s
> on a 1Gbit/s link. The reason is a high interrupt load with interrupts
> every ~20us.
Not my area of expertise, but is NAPI working correctly? It should be
that you disable interrupts while NAPI is polling, and only re-enable
interrupts when polling has stopped. If you are receiving at near line
rate at 100% load, i would of thought that NAPI would be polling most
of the time and interrupts would be mostly disabled?
Interrupt coalescence makes a lot of sense thought, so the patch
itself is useful.
Andrew
next prev parent reply other threads:[~2022-11-17 20:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-17 20:14 [PATCH net-next 0/4] tsnep: Throttle irq, rotten pkts, RX buffer alloc and ethtool_get_channels() Gerhard Engleder
2022-11-17 20:14 ` [PATCH net-next 1/4] tsnep: Throttle interrupts Gerhard Engleder
2022-11-17 20:33 ` Andrew Lunn [this message]
2022-11-18 5:50 ` Gerhard Engleder
2022-11-19 1:24 ` Jakub Kicinski
2022-11-19 20:46 ` Gerhard Engleder
2022-11-17 20:14 ` [PATCH net-next 2/4] tsnep: Fix rotten packets Gerhard Engleder
2022-11-17 20:39 ` Andrew Lunn
2022-11-18 6:13 ` Gerhard Engleder
2022-11-19 1:26 ` Jakub Kicinski
2022-11-19 20:47 ` Gerhard Engleder
2022-11-17 20:14 ` [PATCH net-next 3/4] tsnep: Add ethtool get_channels support Gerhard Engleder
2022-11-17 20:14 ` [PATCH net-next 4/4] tsnep: Rework RX buffer allocation Gerhard Engleder
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Y3aatP+384keCkpN@lunn.ch \
--to=andrew@lunn.ch \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=gerhard@engleder-embedded.com \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).