Table of Contents

Overview

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You can find more details about this option here:  http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/open-source-kernel-enhancements-paper.pdf Intel Whitepaper - Open Source Kernel Enhancements for Low-Latency Sockets using Busy Poll

Linux kernel support:

Kernel should be built with CONFIG_NET_RX_BUSY_POLL compilation option which is enabled by default in RHEL 7.x, no changes are needed for this OS.

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Test Results

A modified Benchmark/Latency test was used in these tests. There were inserted 10ms delays between posts to make the test more realistic and the message rate similar to what occurs in practice. Number of messages = 1000.

The test was conducted on RHEL7.1, i7 3.6 GHz CPU, Myricom 10G NICs; packages were passed through 10G cross-over cable, everything was installed on a single machine.

1. SO_BUSY_POLL is enabled using SocketBusyPollTime. This is a new mode.

   Code Block
   language bash
   Session.target/sender.SocketBusyPollTime = 600000 Session.target/sender.AggressiveReceiveDelay = 500 System::Thread::sleep(10) iterations = 1,000

   Total latency (nanoseconds):   <- time from sending till receiving the message
   MIN: 13549
   MAX: 130952
   AVG: 16396
   
   

2. SO_BUSY_POLL is disabled.
   Total latency (nanoseconds):
   MIN: 39530
   MAX: 166082
   AVG: 47499
   
   

3. SO_BUSY_POLL is disabled, but “busy poll” is enabled inside of Antenna using installation.

   Code Block
   language bash
   Session.target/sender.AggressiveReceiveDelay = 0

   Total latency (nanoseconds):
   MIN: 15854
   MAX: 123549
   AVG: 18831

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