Expand Configuration and Management Manual (H06.21+, J06.10+)

Tuning
Expand Configuration and Management Manual — 529522-013
19 - 4
Multipacket Frame Size
Figure 19-1 shows throughput gains and losses resulting from the use of multipacket
frames.
Processor Use and Message Size
Multipacket frames can improve the processor efficiency of all line types. Direct-
connect and satellite-connect lines benefit when the average message size is less than
500 words; using multipacket frames for these configurations decreases the number of
interrupts, reducing the number of times the direct-connect or satellite-connect line-
handler process is dispatched and causing a reduction in processor use.
There is no improvement in throughput or response time when using multip
acket
frames over fixed bandwidth facilities.
Latency and Multi-Line Paths
On multi-line paths, applications that send messages just below the size of the
configured multipacket frame size might experience higher latency because all data is
sent across only one line. For more information on the multi-line paths, see
Multi-Line
Paths on page 19-13.
Figure 19-1. Throughput With and Without Multipacket Frames
1600
1400
1200
0
200
400
600
800
1000
1800
132 516 744
Framesize (in words)
Single-packet Multipacket
Kilobits per second
VST074.vsd