TY - GEN
T1 - Effects and implications of file size/service time correlation on web server scheduling policies
AU - Lu, Dong
AU - Dinda, Peter A
AU - Qiao, Yi
AU - Sheng, Huanyuan
N1 - Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2005
Y1 - 2005
N2 - Recently, size-based policies such as SRPT and FSP have been proposed for scheduling requests in web servers. SRPT and FSP are superior to policies that ignore request size, such as PS, in both efficiency and fairness, given heavy-tailed service times. However, a central assumption that is usually made in implementing size-based policies in a web server is that the service time of a request is strongly correlated with the size of the file it serves. By collecting web server trace data taken from the logs of modified Apache web servers, this paper reveals that the correlation between service time and file size can be quite low, and shows how the performance of SRPT and FSP can be dramatically affected by the weak correlation via trace-driven simulations. In response, we propose and evaluate domain-based scheduling, a simple technique that better estimates connection times by making use of the source IP address of the request. Domain-based scheduling improves SRPT and FSP performance on web servers, bringing the performance benefits of these scheduling polices even to those regimes where the correlation between file size and service time is low.
AB - Recently, size-based policies such as SRPT and FSP have been proposed for scheduling requests in web servers. SRPT and FSP are superior to policies that ignore request size, such as PS, in both efficiency and fairness, given heavy-tailed service times. However, a central assumption that is usually made in implementing size-based policies in a web server is that the service time of a request is strongly correlated with the size of the file it serves. By collecting web server trace data taken from the logs of modified Apache web servers, this paper reveals that the correlation between service time and file size can be quite low, and shows how the performance of SRPT and FSP can be dramatically affected by the weak correlation via trace-driven simulations. In response, we propose and evaluate domain-based scheduling, a simple technique that better estimates connection times by making use of the source IP address of the request. Domain-based scheduling improves SRPT and FSP performance on web servers, bringing the performance benefits of these scheduling polices even to those regimes where the correlation between file size and service time is low.
UR - http://www.scopus.com/inward/record.url?scp=33646913574&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33646913574&partnerID=8YFLogxK
U2 - 10.1109/MASCOTS.2005.30
DO - 10.1109/MASCOTS.2005.30
M3 - Conference contribution
AN - SCOPUS:33646913574
SN - 0769524583
SN - 9780769524580
T3 - Proceedings - IEEE Computer Society's Annual International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunications Systems, MASCOTS
SP - 258
EP - 267
BT - MASCOTS 2005
T2 - MASCOTS 2005: 13th IEEE International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunications Systems
Y2 - 27 September 2005 through 29 September 2005
ER -