From 32d1b8063ef7a1b1cf20012d2cfbce659d70f3a0 Mon Sep 17 00:00:00 2001 From: Jonathan Rubenstein Date: Sun, 16 Feb 2025 00:54:42 +0200 Subject: [PATCH] [doc] requirements: Modify language of DMABUF for iGPUS --- doc/requirements.rst | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/doc/requirements.rst b/doc/requirements.rst index 44576a4c..9a8215c4 100644 --- a/doc/requirements.rst +++ b/doc/requirements.rst @@ -82,17 +82,16 @@ Linux kernel unless you use the open source NVIDIA drivers. iGPUs should use DMABUF ^^^^^^^^^^^^^^^^^^^^^^^ -While `DMABUF` with the `KVMFR module ` offers performance +While `DMABUF` with the :doc:`KVMFR module ` offers performance benefits for all users, for the often bandwidth-starved users with an iGPU on -their host it's considered necessary for a decent experience. +their host it's considered a requirement for a decent experience. When using a normal SHM file, many GPU drivers will copy incoming frames from shared memory to an intermediary buffer, then upload it from that buffer to the -GPU's framebuffer. The KVMFR module will instead use the GPU's copy engine to -download incoming frames directly from shared memory without using an -intermediary buffer. This is especially helpful to iGPU users as it frees up RAM -bandwidth, which an iGPU already uses extensively. +GPU's framebuffer. The KVMFR module will instead use Direct Memory Access (DMA) +to download incoming frames directly from shared memory, which may depending on +GPU design eliminate the intermediary buffer. This is especially helpful to iGPU +users as it frees up RAM bandwidth, which an iGPU already uses extensively. -An added benefit: since the upload is done with the iGPU's copy engine, the CPU -load is reduced as the upload is done by the iGPU module rather than the -processor cores. +An added benefit: since the upload is done with the iGPU, the CPU load is +reduced as the upload does not use processor cores.