Oh dear ... instead of "and in [6]", I should have written "and in [3]".
On Tue, Feb 23, 2021 at 11:21 PM Etienne-Victor Depasquale <ed...@ieee.org> wrote: > 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 > -- 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
