The Performance Impact of Scheduling for Cache
Affinity in Parallel Network Processing
James Salehi,
James Kurose,
and
Don
Towsley
Computer Networks Research
Group,
Department
of Computer Science,
Lederle Graduate Research Center,
University of
Massachusetts
Amherst, MA 01003-4610
Abstract
We explore processor-cache affinity scheduling of parallel network protocol
processing, in a setting in which protocol processing executes on a
shared-memory multiprocessor concurrently with a general workload of
non-protocol activity. We find affinity-based scheduling can significantly
reduce the communication delay associated with protocol processing, enabling
the host to support a greater number of concurrent streams and to provide
higher maximum throughput to individual streams. In addition, we compare the
performance of two parallelization alternatives, Locking
and Independent Protocol Stacks (IPS), with very different caching
behaviors. We find that
IPS (which maximizes cache affinity) delivers much lower message latency and
significantly higher message throughput capacity, yet exhibits less robust
response to intra-stream burstiness and limited intra-stream scalability.
Keywords
operating systems, computer networks, network protocol processing,
shared-memory multiprocessor, scheduling, processor caches, processor-cache
affinity scheduling, performance evaluation