In [20], we fixed the number of streams at eight, and examined
the performance of receive-side UDP/IP/FDDI processing while
varying the mean packet rate of the individual streams. How
does affinity-based scheduling perform when a large number of
streams are concurrently supported? In this section we address
this question by varying the number of admitted streams, while
for simplicity holding the per-stream packet rate constant (at 125
packets/s). This is more representative of multiprocessor server
applications, such as file and web servers, which must support a
varying and potentially large number of concurrent streams.
Results are shown for an 8-processor host, with a matching
number of independent stacks under CLP so that all processors
can work concurrently. Protocol processingdoes not include datatouching
operations, such as copying or checksumming; these
are considered in Section 5. Packet arrivals are modeled with
an exponential interarrival time; the more realistic Packet-Train
model 191, which captures stream burstiness and source locality,
is considered in Section 7.