Brendan's blog » visualizations

Memory Leak (and Growth) Flame Graphs

Memory Leak Memory Flame Graph     Your application memory usage is steadily growing, and you are racing against time to fix it. This could either be memory growth due to a misconfig, or a memory leak due to a software bug. For some applications, performance can begin to degrade as garbage collection works harder, [...]

Posted on August 16, 2013 at 8:31 am by Brendan Gregg · Permalink · Comments Closed
In: Performance · Tagged with: , , ,

What the Mean Really Means

When analyzing response time, or latency, you need much more information than an average provides. The average, commonly the arithmetic mean, shows the index of central tendency. But, as I found in earlier posts, the tendency is often not central, but may be skewed by outliers, or split by multiple modes. How often these factors [...]

Posted on July 12, 2013 at 10:07 am by Brendan Gregg · Permalink · 2 Comments
In: Uncategorized · Tagged with: , , , ,

Modes and Modality

It is a truth universally acknowledged that the average is the index of central tendency. But what if the tendency isn’t central? I’ve worked many performance issues where the latency or response time was multimodal, and higher-latency modes turned out to be the cause of the problem. Their existence isn’t shown by the average – [...]

Posted on July 8, 2013 at 12:59 pm by Brendan Gregg · Permalink · 2 Comments
In: Performance · Tagged with: , , ,