Bulk Throughput Measurements - LANL, New Mexico
Bulk Throughput Measurements | Bulk Throughput Simulation | Windows vs. streams | Effect of load on RTT and loss | Bulk file transfer measurements
The window buffer sizes on plop on November 5th were the default of 64Kbytes are shown
below. It is seen that the limited window sizes of 64kBytes result in no change
in performance as the requested window size goes above 32KBytes (bear in mind
iperf on Linux gives twice the window size requested). However despite this
limitation the maxima reach over 120 Mbps which is not bad considering the SLAC
link was an ATM OC3 (155Mbps) link.
On November 6th plop was upgraded to Linux 2.4 and the window buffer sizes set
:more /proc/sys/net/core/wmem_max = 2097152
;more /proc/sys/net/core/rmem_max = 2097152
;more /proc/sys/net/core/rmem_default = 65535
;more /proc/sys/net/core/wmem_default = 65535
;more /proc/sys/net/ipv4/tcp_rmem = 4096 87380 2097152
;more /proc/sys/net/ipv4/tcp_wmem = 4096 16384 2097152
In addition the link from pharlap to ESnet was upgraded to OC12 Packet Over SoNet (POS) (622Mbps). The bandwidth was measured with pipechar. The iperf improvement is striking and seen below. The maxima went for 120Mbps to over 400Mbps.