intel_gtt

intel_gtt

The `intel_gtt` command is a debugging tool primarily used to inspect and manipulate the Graphics Translation Table (GTT) on Intel integrated graphics. The GTT is a crucial component for memory management, allowing the CPU and GPU to efficiently share and access memory. It allows examining the current GTT setup, including the size of the GTT aperture, the location of the GTT page table in physical memory, and the contents of the GTT entries themselves.

This tool can be useful for diagnosing memory-related issues in graphics drivers, understanding how memory is being allocated between the CPU and GPU, and verifying the correctness of GTT setup and operations. Note that this utility often requires root privileges to access the necessary hardware resources. While not a standard command-line tool available on every system, it's often found in distributions used for graphics driver development and testing.

Due to its potential to destabilize the system if misused, `intel_gtt` is generally used in development or debugging environments, not in production.

Misuse can lead to system instability or crashes. Requires root privileges in most cases. Availability depends on the specific kernel and drivers.

The Graphics Translation Table (GTT) is essentially a page table that maps virtual addresses to physical memory addresses specifically for the GPU. This allows the GPU to access system memory (or dedicated graphics memory, if available) as if it were contiguous, even if the actual memory is fragmented. The GTT enables efficient data transfer and sharing between the CPU and GPU.

Typical use cases involve verifying GTT setup after driver initialization, troubleshooting memory allocation errors in graphics applications, and analyzing GTT performance to identify bottlenecks. It is also used to diagnose memory leaks related to graphics contexts.

Typically, this utility interacts directly with kernel drivers via ioctl calls to read and potentially modify registers and memory related to the GTT. The exact implementation is closely tied to the Intel graphics driver version and kernel version.

The `intel_gtt` tool emerged alongside the development of Intel integrated graphics and the Direct Rendering Manager (DRM) subsystem in the Linux kernel. Its creation was driven by the need to debug and fine-tune memory management between the CPU and GPU. It evolved as the complexity of Intel graphics architectures grew, providing deeper insights into the GTT and its role in graphics performance and stability. Its focus is driver debugging not every end user is supposed to use it.

lspci(8), drm(7)