nus.soc.cs5248 Ooi Wei Tsang Recent Papers from conferences

nus.soc.cs5248 Ooi Wei Tsang Sessions Session 1: Movies and Music Session 2: Peer-to-Peer Streaming Session 3: Power-Friendly

nus.soc.cs5248 Ooi Wei Tsang Movies and Music Session 1

nus.soc.cs5248 Ooi Wei Tsang Characterizing DVD Wu-Chi Feng et. al. Packet Video 2003

nus.soc.cs5248 Ooi Wei Tsang Motivations Lots of DVD videos available How are they encoded? What is the implications to our research?

nus.soc.cs5248 Ooi Wei Tsang DVD data 107 video streams 140 hours 80 DVDs

nus.soc.cs5248 Ooi Wei Tsang Bit-rates Maximum DVD bit rates 10 Mbps Found on DVD 3.3 – 7.8 Mbps VBR Quantization values change over time (only Spy Kids is CBR)

nus.soc.cs5248 Ooi Wei Tsang GOPs and Sequences Each GOP was encoded into a different sequence GOP sizes: around 12 frames

NUS.SOC.CS5248 OOI Wei Tsang nus.soc.cs5248 Ooi Wei Tsang Sequence sequence header: width height frame rate bit rate :

NUS.SOC.CS5248 OOI Wei Tsang nus.soc.cs5248 Ooi Wei Tsang GOP: Group of Picture gop header: time :

NUS.SOC.CS5248 OOI Wei Tsang nus.soc.cs5248 Ooi Wei Tsang Picture pic header: number type (I,P,B) :

nus.soc.cs5248 Ooi Wei Tsang Frame Patterns Most videos have varying Number of frames within a GOP Frame patterns (ID4 has 134 unique GOP patterns)

nus.soc.cs5248 Ooi Wei Tsang Frame Pattern Scene Change Detection used extensively IPPPPPPP quite common!

nus.soc.cs5248 Ooi Wei Tsang Implication to Research Cannot assume fixed frame pattern Cannot always drop B frames

nus.soc.cs5248 Ooi Wei Tsang Network Musical Performances UC Berkeley NOSSDAV 2001

nus.soc.cs5248 Ooi Wei Tsang Goal Show that networked musical performances (NMP) can be done

nus.soc.cs5248 Ooi Wei Tsang Observation Stanford – Berkeley (40 miles) RTT ~4 ms 0.72 meters Berkeley – Caltech (375 miles) RTT ~28 ms 4.88 meters

nus.soc.cs5248 Ooi Wei Tsang Observation Musical instruments have long production latency

nus.soc.cs5248 Ooi Wei Tsang Observation Don’t send audio, send command Keeps “states” of the current music performance

nus.soc.cs5248 Ooi Wei Tsang Example NoteOn(channel, note, velocity) NoteOff(channel, note)

nus.soc.cs5248 Ooi Wei Tsang Packet Loss Recovery Lost/Late NoteOn skipped Lost/Late NoteOff executed

nus.soc.cs5248 Ooi Wei Tsang Packet Loss Recovery Guard packets Recovery journals

nus.soc.cs5248 Ooi Wei Tsang Bandwidth 20 MIDI command per seconds 640 bps With recovery journals ~7 kbps

nus.soc.cs5248 Ooi Wei Tsang Experience Lost/Late NoteOn/NoteOff But musician can adjust and play fluidly

nus.soc.cs5248 Ooi Wei Tsang Peer-to-Peer Session 2

nus.soc.cs5248 Ooi Wei Tsang P2Cast Yang Guo et. al. WWW 2003

nus.soc.cs5248 Ooi Wei TsangNUS.SOC.CS5248 OOI WEI TSANG Patching Time Client Request mcast unicast

nus.soc.cs5248 Ooi Wei TsangNUS.SOC.CS5248 OOI WEI TSANG Patching Time Client Request Patching Window: W mcast

nus.soc.cs5248 Ooi Wei Tsang Problem with VOD IP Multicast usually assumed Patching still requires unicast connections

nus.soc.cs5248 Ooi Wei Tsang P2Cast

nus.soc.cs5248 Ooi Wei Tsang New Session

nus.soc.cs5248 Ooi Wei Tsang Existing Session + Patch ? ? Fat Pipe First

nus.soc.cs5248 Ooi Wei Tsang Patch Server Selection

nus.soc.cs5248 Ooi Wei Tsang Patching Stream patching stream base stream

nus.soc.cs5248 Ooi Wei Tsang Tree Example

nus.soc.cs5248 Ooi Wei Tsang Failure Recovery X

nus.soc.cs5248 Ooi Wei Tsang Failure Recovery What if Patch server failed? Base server failed?

nus.soc.cs5248 Ooi Wei Tsang PROMISE Mohamed Hafeeda et. al. ACM MM 2003

nus.soc.cs5248 Ooi Wei Tsang Problem P2P with streaming One peer may not have enough bandwidth Need to aggregate multiple peers

nus.soc.cs5248 Ooi Wei Tsang Architecture B/2 B/4 CollectCast

nus.soc.cs5248 Ooi Wei Tsang CollectCast Select sending peers Monitor network Assign streaming rates and data segments Decide when to change peers

nus.soc.cs5248 Ooi Wei Tsang PROMISE Operations I want to watch LOTR:T2T

nus.soc.cs5248 Ooi Wei Tsang PROMISE Operations These are the candidate s..

nus.soc.cs5248 Ooi Wei Tsang PROMISE Operations Max expected goodness Subject to rate constraints

nus.soc.cs5248 Ooi Wei Tsang PROMISE Operations Here are your peers!

nus.soc.cs5248 Ooi Wei Tsang PROMISE Operations Send these..

nus.soc.cs5248 Ooi Wei Tsang PROMISE Operations Should I switch?

nus.soc.cs5248 Ooi Wei Tsang PALS Reza Rejaie et. al. NOSSDAV 2003

nus.soc.cs5248 Ooi Wei Tsang Problem P2P with streaming One peer may not have enough bandwidth Need to aggregate multiple peers Using layered coding With congestion control

nus.soc.cs5248 Ooi Wei Tsang Sliding Window playout time window

nus.soc.cs5248 Ooi Wei Tsang Packet Assignment playout time S1S2

nus.soc.cs5248 Ooi Wei Tsang Sending Mechanism Request packets in priority order Sender must send in order Next request overwrites previous one

nus.soc.cs5248 Ooi Wei Tsang Power-Friendly Session 3

nus.soc.cs5248 Ooi Wei Tsang GRACE-OS Wanghong Yuan SOSP 2003

nus.soc.cs5248 Ooi Wei Tsang Motivation Mobile devices run on battery How to save battery?

nus.soc.cs5248 Ooi Wei Tsang Dynamic Voltage Scaling Example: AMD Athlon 4 PowerOn {300, 500, 600, 700, 800, 1000}MHz Energy  V 2

nus.soc.cs5248 Ooi Wei Tsang CPU Scheduler When to execute a task How long to execute it How fast to execute it

nus.soc.cs5248 Ooi Wei TsangNUS.SOC.CS5248 OOI WEI TSANG CPU Reservation “I need C units of time, out of every T units.”

nus.soc.cs5248 Ooi Wei Tsang Probability Distribution cycles Cum. Prob % of the time, this task requires 500 cycle.

nus.soc.cs5248 Ooi Wei Tsang CPU Requirements “I need C units of time, out of every T units.” CPU only needs to run at “With 80% success rate, C is 500 cycle”

nus.soc.cs5248 Ooi Wei Tsang Speed Schedule speed time If task can finish early, we save energy by not running it at higher speed

nus.soc.cs5248 Ooi Wei Tsang Finding Speed Schedule Let task execute at speed v x during cycle x execution time: 1/v x power:  v x 2 average power:  (1-F(x))v x 2

nus.soc.cs5248 Ooi Wei Tsang Optimize This Minimize: Subjected to:

nus.soc.cs5248 Ooi Wei Tsang Implementation Linux Kernel AMD Athlon lines of code

nus.soc.cs5248 Ooi Wei Tsang Findings Probability distribution is quite stable Able to meet deadlines with bounded miss ratio Save energy by 7 – 72%

nus.soc.cs5248 Ooi Wei Tsang Proxy Assisted Streaming Prashant Shenoy et. al. MMCN 2003

nus.soc.cs5248 Ooi Wei Tsang Motivation Power-aware streaming to mobile device save energy in decoding frames save energy in receiving packets

nus.soc.cs5248 Ooi Wei Tsang Architecture server/proxyclient Here’s my energy budget for decoding + network reception and max resolution

nus.soc.cs5248 Ooi Wei Tsang Architecture server/proxyclient OK, what should I send?

nus.soc.cs5248 Ooi Wei Tsang Information Needed Map stream properties to energy requirement Need to know decoding time of a frame

nus.soc.cs5248 Ooi Wei Tsang Frame Decoding Time Frame Size (bits) Time (s)

nus.soc.cs5248 Ooi Wei Tsang Transcoding If current stream would exceed client decoding energy budget Need to transcode by reducing quality

nus.soc.cs5248 Ooi Wei Tsang Transcode to what? E = estimated energy needed while E > energy budget reduce quality by ε E = estimate energy needed

nus.soc.cs5248 Ooi Wei Tsang Transcoded Streams server/proxyclient

nus.soc.cs5248 Ooi Wei Tsang Reducing NIC Energy NIC has two modes : active/sleep Client can activate NIC only when packets are expected.

nus.soc.cs5248 Ooi Wei Tsang Burst Transmission I will start transmitting at 10:12:54.86 pm

nus.soc.cs5248 Ooi Wei Tsang Evaluations Decoding Time Frame Number

nus.soc.cs5248 Ooi Wei Tsang Evaluations NIC Idle Uptime: 2 – 20%