Characterize Energy Impact of Concurrent Network- Intensive Applica=ons on Mobile PlaAorms

Transcription

1 ACM MobiArch 2013 Characterize Energy Impact of Concurrent Network- Intensive Applica=ons on Mobile PlaAorms Zhonghon Ou, Shichao Dong, Jiang Dong, Jukka K. Nurminen, AnH Ylä- Jääski Aalto University, Finland Ren Wang Intel Labs

2 Number of mobile apps

3 Takeaway: Number of mobile apps increases significantly, amongst them plenty need network connec=vity to func=on properly.

4 Network speed increasing

5 Takeaway: Network speed advancement enables opportuni=es that was not possible before.

6 Energy hogs

7 Takeaway: network communica=ons (especially cellular communica=ons) accounts for a large part of power consump=on of the overall mobile plaaorm. Source: Carroll et al. An Analysis of Power Consump=on in a Smartphone, USENIX ATC 10.

8 Ques=ons to answer

9 Q1: Can mul=ple network- intensive applica=ons running concurrently save energy? If yes, how much saving can it achieve?

10 Q2: What is the domina=ng factor of energy dynamics, network interface or CPU, in network ac=vi=es?

11 What we did?

12 Profile different combina=ons of applica=ons, including, VoIP, data transmission, video streaming etc, to understand their energy impact on mobile plaaorm, and to inves=gate opportuni=es to save energy for mobile plaaorms.

13 Experiment setup

14 Experiment setup Power consump=on Mosoon power monitor TCP throughput Customized small apps Signal strength Readings from Android API

15 Measurements

16 Power vs. CPU u=liza=on ra=o Takeaway: Power consump=on follows linearly with CPU u=liza=on ra=o. The idle power consump=on is rela=vely big though. P(x) = 9.2 x (mw)

17 Power consump=on vs. throughput

18 Download power vs. CPU u=liza=on 1100 Kbps 6000 Power Consumption (mw) Power Consumption (mw) Power Difference (mw) Network Throughput (Kbps) CPU Utilization Ratio (%) Takeaway: power consump=on increases as network throughput, but the difference between whole plaaorm power and CPU power does not change so much.

19 Upload power vs. CPU u=liza=on Power Consumption (mw) Power Consumption (mw) Power Difference (mw) Network Throughput (Kbps) Kbps CPU Utilization Ratio (%) Takeaway: same trend as downlink is also observed for uplink. The power difference is even more stable than for downlink.

20 Mul=ple concurrent TCP connec=ons for the same type of applica=on

21 Aggregate Takeaway: number of TCP connec=ons does not maaer much as long as the accumulated network throughput is the same. More TCP connec=ons mean each TCP connec=on acquires a smaller por=on of the available bandwidth.

22 Mul=ple concurrent applica=ons

23 Takeaway: Adding one extra applica=on only slightly increases the overall power consump=on. Power saving by running two or more applica=ons concurrently compared to running them separately is significant.

24 Illustra=ve example

25 2000 Power Consumption (mw) VoIP Down Up VoIP+Down VoIP+Up VoIP+Down+Up Takeaway: Running mul=ple applica=ons concurrently can amor=ze power consump=on from CPU, SoC and network interface.

26 Take away Addi=onal power cost for suppor=ng a second (third ) applica=on is compara=vely small, when one applica=ons is already triggered. Power consump=on from CPU and System- on- Chip (SoC) is the primary culprit for high- power network ac=vi=es; power consump=on from network interface is rela=vely stable.

27 Impact of signal strength

28 Signal strength vs. throughput Throughput (Kbps) S download S upload S combo upload S combo download Takeaway: conduc=ng uploading and downloading concurrently only slightly impact the network throughput compared to having them separately Signal Strength (dbm) Combo: upload + download concurrently

29 Signal strength vs. power 2000 Power Consumption (mw) S download S upload S combo Signal Strength (dbm) Takeaway: Power consump=on of conduc=ng uploading and downloading concurrently follows very closely with having uploading alone.

30 Implica=ons Schedule downloading when uploading is triggered, e.g. outgoing phone call. Achieve full speed downloading with almost no extra power Schedule mul=ple applica=ons concurrently to amor=ze CPU and SoC power consump=on.

31 Related work Carroll et al. An Analysis of Power Consump=on in a Smartphone, USENEX ATC 10. Schulman et al. Bartendr. Mobicom 10

32 Conclusion Scheduling mul=ple applica=ons concurrently can achieve significant energy saving. Signal strength poses an important factor on power consump=on of mobile plaaorms. Power consump=on from CPU and SoC is the primary culprit for power dynamics of network ac=vi=es, while power from NIC is rela=vely stable.