Overview

This article explains how to start investigating a MemReplay log file. Please refer to Getting Started with MemReplay and Setup and Loading data with MemReplay Tool if you have not yet successfully loaded a zmrl file.

Usage Screen

If you have loaded a zmrl file into the MemReplay Tool you will see something similar to the following screenshot.

The example log file which has been loaded here is showing all the allocations for life cycle:

The By Allocation Event window and the By Frame window both represent the same memory allocations. However, they differ in the way they display them:

• By Allocation Event: Each graph sample represents exactly one allocation (not related to time)
• By Frame: Each graph sample represents exactly one frame (not related to number of allocations or time)

There are three lines with different colors (Requested, Consumed and Pagefile) which have different memory usage meanings:

• Requested: The amount of memory requested by the Engine. This line might be hidden behind the Consumed memory since they usually match
• Consumed: The actual memory in use. This is parameter you are most likely to be interested in
• Pagefile: Consumed memory of process. On PC, it might be that some allocations are performed on a different RAM for e.g. textures on VRAM. Note that Pagefile memory usage only gives information about the actual usage of the process

• Uniform Zooming: Scroll mouse wheel
• Free-Zoom: Hold Middle mouse button and drag mouse
• Panning: Hold Right mouse button and drag mouse

Tracing Memory

The following example shows, how memory allocations are investigated. Select an area inside the By Allocation Event or the By Frame window.

In the top bar, press the D-button which gives you view selection details.

Then press Go!

The Alloc Ev Range is representing the actual selection and can be adjusted if required.

This opens a new tab which looks similar to the one in the following screenshot. By clicking on the green memory block, the callstack on the left is updated.

In this example the memory block and callstack reveal that 6.4MB have been allocated by Create2DTexture() in the range specified.

Selecting the Code tab at the bottom shows you the actual position inside code.

Getting more information about the memory block is easy. Select the memory block you want to explore and click on the C-button on the top bar to show the context tree.

This gives a summary of the items which together form the memory block you have selected.

In this example, the 6.4MB memory block consists of textures such as blood_anim_a.dds, foam_tiled2.dds and others.

A categorized context tree can be generated from Tools -> Build context trees. If no area is selected, then it will be generated for the complete life cycle of the capture log.