DPDK and energy efficiency

Tue Feb 23 07:27:31 UTC 2021

Sorry, last line should have been:
"intended to get an impression of how widespread ***knowledge of*** DPDK's
core operating inefficiency is",
not:
"intended to get an impression of how widespread DPDK's core operating
inefficiency is"

On Tue, Feb 23, 2021 at 8:22 AM Etienne-Victor Depasquale <edepa at ieee.org>
wrote:

> Beyond RX/TX CPU affinity, in DANOS you can further tune power consumption
>> by changing the adaptive polling rate.  It doesn’t, per the survey, "keep
>> utilization at 100% regardless of packet activity.”
>>
> Robert, you seem to be conflating DPDK
> with DANOS' power control algorithms that modulate DPDK's default
> behaviour.
>
> Let me know what you think; otherwise, I'm pretty confident that DPDK does:
>
>> "keep utilization at 100% regardless of packet activity.”
>
>
> Keep in mind that this is a bare-bones survey intended for busy,
> knowledgeable people (the ones you'd find on NANOG) -
> not a detailed breakdown of modes of operation of DPDK or DANOS.
> DPDK has been designed for fast I/O that's unencumbered by the trappings
> of general-purpose OSes,
> and that's the impression that needs to be forefront.
> Power control, as well as any other dimensions of modulation,
> are detailed modes of operation that are well beyond the scope of a
> bare-bones 2-question survey
> intended to get an impression of how widespread DPDK's core operating
> inefficiency is.
>
> Cheers,
>
> Etienne
>
> On Mon, Feb 22, 2021 at 10:20 PM Robert Bays <robert at gdk.org> wrote:
>
>> Beyond RX/TX CPU affinity, in DANOS you can further tune power
>> consumption by changing the adaptive polling rate.  It doesn’t, per the
>> survey, "keep utilization at 100% regardless of packet activity.”  Adaptive
>> polling changes in DPDK optimize for tradeoffs between power consumption,
>> latency/jitter and drops during throughput ramp up periods.  Ideally your
>> DPDK implementation has an algorithm that tries to automatically optimize
>> based on current traffic patterns.
>>
>> In DANOS refer to the “system default dataplane power-profile” config
>> command tree for adaptive polling settings.  Interface RX/TX affinity is
>> configured on a per interface basis under the “interfaces dataplane” config
>> command tree.
>>
>> -robert
>>
>>
>> > On Feb 22, 2021, at 11:46 AM, Jared Geiger <jared at compuwizz.net> wrote:
>> >
>> > DANOS lets you specify how many dataplane cores you use versus control
>> plane cores. So if you put a 16 core host in to handle 2GB of traffic, you
>> can adjust the dataplane worker cores as needed. Control plane cores don't
>> stay at 100% utilization.
>> >
>> > I use that technique plus DANOS runs on VMware (not oversubscribed)
>> which allows me to use the hardware for other VMs. NICS are attached to the
>> VM via PCI Passthrough which helps eliminate the overhead to the VMware
>> hypervisor itself.
>> >
>> > I have an 8 core VM with 4 cores set to dataplane and 4 to control
>> plane. The 4 control plane cores are typically idle only processing BGP
>> route updates, SNMP, logs, etc.
>> >
>> > ~Jared
>> >
>> > On Sun, Feb 21, 2021 at 11:30 PM Etienne-Victor Depasquale <
>> edepa at ieee.org> wrote:
>> > Hello folks,
>> >
>> > I've just followed a thread regarding use of CGNAT and noted a
>> suggestion (regarding DANOS) that includes use of DPDK.
>> >
>> > As I'm interested in the breadth of adoption of DPDK, and as I'm a
>> researcher into energy and power efficiency, I'd love to hear your feedback
>> on your use of power consumption control by DPDK.
>> >
>> > I've drawn up a bare-bones, 2-question survey at this link:
>> >
>> > https://www.surveymonkey.com/r/J886DPY.
>> >
>> > Responses have been set to anonymous.
>> >
>> > Cheers,
>> >
>> > Etienne
>> >
>> > --
>> > Ing. Etienne-Victor Depasquale
>> > Assistant Lecturer
>> > Department of Communications & Computer Engineering
>> > Faculty of Information & Communication Technology
>> > University of Malta
>> > Web. https://www.um.edu.mt/profile/etiennedepasquale
>>
>>
>
> --
> Ing. Etienne-Victor Depasquale
> Assistant Lecturer
> Department of Communications & Computer Engineering
> Faculty of Information & Communication Technology
> University of Malta
> Web. https://www.um.edu.mt/profile/etiennedepasquale
>

-- 
Ing. Etienne-Victor Depasquale
Assistant Lecturer
Department of Communications & Computer Engineering
Faculty of Information & Communication Technology
University of Malta
Web. https://www.um.edu.mt/profile/etiennedepasquale
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