Network Jitter: An In-Depth Case Study

Network Jitter: Symptoms

For a better understanding of the jitter issue, let’s take a look at some of the symptoms of network jitter. In this article, we will consider a scenario in which a user’s application log registers latency of hundreds of milliseconds, and sometimes a latency as long as one to two seconds, along with frequent jitters. Such factors not only dramatically affect services which require a high level of timeliness but also hamper a user’s confidence for migrating data to the cloud.

Network Jitter: Primary Troubleshooting

Through the initial analysis at the application layer, the user suspects that the issue arises from the virtual network environment. However, as the first step, it is critical to further abstract, simplify the problem. Since we don’t have a clear understanding of user-side applications, and are unaware of the specific meanings and recording methods of application logs.

Analysis 1

The above ping test simplifies the problem to the ping gateway latency. However, it is crucial to understand the specific meaning of such regular test results.

Analysis 2

This analysis involves conducting several little troubleshooting experiments, such as writing a kernel driver to disable interruptions and testing whether further information, such as the stack when disabling interruptions, are retrievable using various kernel tracking methods. Unfortunately, in the case of disabling interruptions, no method is applicable to retrieve the kernel stack in a lightweight way without affecting services.

static inline void __spin_lock_irq(spinlock_t *lock){local_irq_disable();

Original Source:

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