>The thread for longer files is more likely to be in the middle of a >transfer, and thus capable of boosting its throughput, while the other >thread suffers low throughput due to starting or stopping the transfer of >an individual file. Maybe. Certainly "The thread for longer files is more likely to be in the middle of a transfer" is true, but "capable of boosting its throughput" is suspect. High-volume servers may optimize overall performance using estimates of the effective bandwidth to each client system. Server resources are then managed to deliver data for that client at no faster rate, if useful work for other clients can be performed. The purpose of this strategy is to avoid use of server resources to send additional data to a client when it is reasonable to believe network conditions are unlikely to permit any faster delivery than if that data were sent at a measured effective data rate. The server does not want its optimization strategy flummoxed by something like a router's "fair share" algorithm that may cause significant variations in individual message processing times. Of course, network performance is a dynamic thing, and estimates of effective bandwidth must be updated over time - but this time is likely to be much longer than the time needed to start or stop an individual transfer operation. Even when server resources are not currently strained, optimization strategies are likely to be in use because (1) they are not believed to significantly degrade performance under less heavy load and (2) server load is erratic, therefore it is simpler and better to always have optimization active than to try to switch it on just when it may be needed. That said, it looks to me like dl.fedoraproject.org does not use such an optimization strategy. On the other hand, kernel.org does, and takes about five seconds to reach my maximum bandwidth of 2 Mbytes per second. Please do not take any of this as criticism of the use of multiple threads for data transfer operations. I strongly support that notion, and would argue more than two threads may be desirable. While much less frequent than I used to see, there are still times when I find data transfer operations seriously degraded by what appears to be packet loss, and consequent long delays until a system retransmits a message. Many threads is not a perfect solution, but it is much more aggreable to see significant network activity than just the occasional retransmission of a message to recover from lost packets. -- test mailing list test@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe: https://admin.fedoraproject.org/mailman/listinfo/test
