[Bug 281252] Framebuffer writes are very slow on BeagleBone Black
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Date: Tue, 03 Sep 2024 19:37:36 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=281252 Bug ID: 281252 Summary: Framebuffer writes are very slow on BeagleBone Black Product: Base System Version: 13.4-STABLE Hardware: arm OS: Any Status: New Severity: Affects Only Me Priority: --- Component: arm Assignee: freebsd-arm@FreeBSD.org Reporter: prog@msobczak.com A simple test with video framebuffer, composed of just: 1. open("/dev/fb0", ...) 2. mmap(...) on the file descriptor 3. memset(buf, ...) over any portion of the framebuffer area, is very slow, compared to Linux Debian on the same board. While the above test operates within a blink of an eye on Linux, its execution on FreeBSD 13.x runs in apparently constant, but very low speed - taking about 2s to fill the whole framebuffer of reasonable size (whether 1280x1024 or 1024x768). Such timings make the whole concept of framebuffer somewhat useless. While the test runs, the main console also displays a number of messages as already reported in: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=241428 It looks as if there is some checking/monitoring/etc. of every single write while they traverse through the VM layers. Or, perhaps, a misconfigured orchestration with the underlying hardware (framer DMA, etc.). -- You are receiving this mail because: You are the assignee for the bug.