7.6.1. Program trace view basics

While the disassembly view provides an overview of each instruction's performance by providing execution counts and timing statistics, the trace view is a sequential list of all executed instructions. Here, every instance of every instruction is listed in the order of execution. If a loop is called 100,000 times, the instructions that make up that loop will repeat 100,000 times in the trace view.

Figure 7.8. The program trace view with a cycle accurate capture

The program trace view with a cycle accurate capture

The centered light green highlight and the yellow arrow show the current trace position. The green box on the right of the highlighted instruction is a CPI histogram and it only appears in the program trace view if the sampling rate was set to cycle accurate for the captured execution. The small graph shows the incidence rates of CPI values caused by this instruction and any instances of the instructions within a range of 100,000 instructions above or below it. For example, if there are 10 instances of a given instruction within the +/- 100,000 range of the current trace position and 5 had a CPI value between 0 and 9 and 5 with a value between 41 and 50 due to cache effects, two equal bars would appear in this chart, one on the far left that represents the five values between 0 and 9 and one in the middle that represents the values between 41 and 50. No other bars would appear in the chart, as no other CPI values exist in the given +- 100, 000 range. Click on any bar for a tooltip that tells you the CPI range the bar represents and how many instances of the instruction fall in that range. Hold the mouse button down and drag across all bars to see information on each.

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