Check out the new USENIX Web site. next up previous
Next: Common case Up: Performance evaluation Previous: Impact on Communication Setup

Impact on Data Transfer

The impact of operating system on the performance of user-level data transfer is quite limited. In VMMC, the OS involvement is needed only when the address translation is not available in the UTLB translation table. To evaluate this effect, we first measure the performance in the common case in which all the address translation is in the UTLB translation table and therefore has no operating system involvement. We then measure the UTLB overheads when the translations are not available in the translation table. Finally we measure the UTLB overheads in a few real applications and parallel programs.

   figure386
Figure 4: Remote send latency for small messages

   figure391
Figure 5: One-way send bandwidth





Yuqun (Michael) Chen
Wed Jun 2 19:35:36 EDT 1999