This paper presents two optimizations to improve the network receive performance in Xen, espe- cially for receiving small packets, by reducing per-packet overhead of network virtualization. First, the universal receiv...This paper presents two optimizations to improve the network receive performance in Xen, espe- cially for receiving small packets, by reducing per-packet overhead of network virtualization. First, the universal receive aggregation assembles incoming packets to decrease the cost of software bridge and bridge netfilter, no matter which protocol these packets use or whether they belong to the same TCP link. Second, the grant page sharing makes as many packets as possible share a single grant page to decrease the cost of expensive grant operations effectively. Experiment demonstrates that compared with default network virtualization in Xen, these two optimizations can reduce CPU cycles per packet by 31.20%, and improve UDP and TCP throughput by 37.73% and 25.62% on average.展开更多
Simulated annealing is a new kind of random search methods developed in recent years.it can also be considered as an extension to the classical hill-climbing method in AI——probabilistic hill-cimbing.One of its most ...Simulated annealing is a new kind of random search methods developed in recent years.it can also be considered as an extension to the classical hill-climbing method in AI——probabilistic hill-cimbing.One of its most important features is its global convergence.The convergence of simulated annealing algorithm is determined by state generating probability,state accepting probability,and temperature decreasing rate.This paper gives a generalized simulated annealing algorithm with dynamic generating and accepting probabilities.The paper also shows that the generating and accepting probabilities can adopt many different kinds of distributions while the global convergence is guaranteed.展开更多
文摘This paper presents two optimizations to improve the network receive performance in Xen, espe- cially for receiving small packets, by reducing per-packet overhead of network virtualization. First, the universal receive aggregation assembles incoming packets to decrease the cost of software bridge and bridge netfilter, no matter which protocol these packets use or whether they belong to the same TCP link. Second, the grant page sharing makes as many packets as possible share a single grant page to decrease the cost of expensive grant operations effectively. Experiment demonstrates that compared with default network virtualization in Xen, these two optimizations can reduce CPU cycles per packet by 31.20%, and improve UDP and TCP throughput by 37.73% and 25.62% on average.
基金This research is supported by the National 863 Project of China.
文摘Simulated annealing is a new kind of random search methods developed in recent years.it can also be considered as an extension to the classical hill-climbing method in AI——probabilistic hill-cimbing.One of its most important features is its global convergence.The convergence of simulated annealing algorithm is determined by state generating probability,state accepting probability,and temperature decreasing rate.This paper gives a generalized simulated annealing algorithm with dynamic generating and accepting probabilities.The paper also shows that the generating and accepting probabilities can adopt many different kinds of distributions while the global convergence is guaranteed.
