> > DPDK doesn't inherently do much in the way of power management. > I agree - it doesn't. That's not what it was made for.
Note that DPDK applications are usually intended to run in very-high data rate environments where no gains are likely to be realized by avoiding a busy-wait loop. That's not what research shows. Use of LPI states is proposed for power management under high data rate conditions in [5] and in [6], use of the low-power instruction *halt * is investigated and found to save power under such conditions. Cheers, Etienne [3] X. Li, W. Cheng, T. Zhang, F. Ren, and B. Yang, “Towards Power Efficient High Performance Packet I/O,” IEEE Transactions on Parallel and Distributed Systems, vol. 31, no. 4, pp. 981–996, April 2020, ISSN:1558-2183. DOI: 10.1109/TPDS.2019.2957746 [5] R. Bolla, R. Bruschi, F. Davoli, and J. F. Pajo, “A Model-Based Approach Towards Real-Time Analytics in NFV Infrastructures,” IEEE Transactions on Green Communications and Networking, vol. 4, no. 2, pp. 529–541, Jun. 2020, ISSN: 2473-2400. DOI: 10.1109/TGCN.2019.2961192. On Tue, Feb 23, 2021 at 11:04 PM William Herrin <b...@herrin.us> wrote: > On Mon, Feb 22, 2021 at 11:24 PM Etienne-Victor Depasquale > <ed...@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. > > Keep in mind that this is a bare-bones survey intended for busy, > knowledgeable people (the ones you'd find on NANOG) - > > Hi, > > Since you understand that, I'm not really clear what you're asking in > the survey. > > DPDK doesn't inherently do much in the way of power management. The > polling loops are in the application side of the software, not the > DPDK libraries or NIC driver. It's up to the application author to > decide to detect idleness in the polling loop and take action to > reduce CPU load. If they go for a simple busy-wait, the dataplane > cores run at 100% all the time regardless of packet load. This has the > expected impact on the server's power consumption. > > Note that DPDK applications are usually intended to run in very-high > data rate environments where no gains are likely to be realized by > avoiding a busy-wait loop. > > Regards, > Bill Herrin > > > -- > William Herrin > b...@herrin.us > https://bill.herrin.us/ > -- 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
