Mesa 21.0 Begins Landing Optimizations For AMD Smart Access Memory

[phoronix]

Phoronix: Mesa 21.0 Begins Landing Optimizations For AMD Smart Access Memory

While AMD Smart Access Memory has already been supported under Linux for some time with its resizable BAR functionality, only now with all the excitement around the feature being promoted with the Ryzen 5000 series and Radeon RX 6000 series hardware is the Mesa driver code beginning to see some optimizations for it...

http://www.phoronix.com/scan.php?page=news_item&px=Mesa-21.0-AMD-Smart-Memory

[CochainComplex]

Michael did you check if it is limited to 5xxx series?

[zboszor]

Michael Please also run OpenGL tests with games and benchmarks using the compatibility profile.
You forgot to report this huge improvement: https://gitlab.freedesktop.org/mesa/..._requests/7078

[khnazile]

micheal did you check if it is limited to 5xxx series?

While I'm not user if Mesa code is limited to 5xxx series, the kernel driver supports resizable BAR for 3xxx, but you also need your motherboard bios to allow this. I'm not sure if it will work for older CPUs.

[libcg_]

While I'm not user if Mesa code is limited to 5xxx series, the kernel driver supports resizable BAR for 3xxx, but you also need your motherboard bios to allow this. I'm not sure if it will work for older CPUs.

On Linux only "Above 4G Decoding" is required. Then you can check with `AMD_DEBUG=info glxinfo | grep vram` if "vram_size" equals "vram_vis_size". It's working for me with a 1700X and R9 Fury.

[CochainComplex]

While I'm not user if Mesa code is limited to 5xxx series, the kernel driver supports resizable BAR for 3xxx, but you also need your motherboard bios to allow this. I'm not sure if it will work for older CPUs.

Thats my point. I want to know if mesa really works with 3xxx or if it is just some cli "read out error" which can not be used by mesa.

[bridgman]

Thats my point. I want to know if mesa really works with 3xxx or if it is just some cli "read out error" which can not be used by mesa.

AFAIK most of the "limited to xxx hardware" statements relate to Windows, where there is some additional work to get large BAR working under all conditions, while Linux worked through most of those issues (mostly SBIOS) a few years ago.

[CochainComplex]

AFAIK most of the "limited to xxx hardware" statements relate to Windows, where there is some additional work to get large BAR working under all conditions, while Linux worked through most of those issues (mostly SBIOS) a few years ago.

thx for clearifing!

edit.: I can confirm 3600XT plus Radeon 5700XT (kernel 5.9 latest git mesa) shows SAM prerequisits.

AMD_DEBUG=info glxinfo | grep vram
vram_size = 8192 MB
vram_vis_size = 8176 MB
vram_type = 9
vram_bit_width = 256
has_dedicated_vram = 1
all_vram_visible = 1


as wirtten by others bios needs to expose the switch. For the asus x570 ace pro this feature is around since few days. Before the new bios it was not exposed as prompted above.

[theriddick]

Still a little bit confused as to why we can't have this on 3000 and 4000 CPU's.... Anyway updated BIOS this morning for my MPG_550_WIFI board, it removed my linux bootloader from the boot list (using windows atm to play CP2077, for now)

[plasticbomb1986]

Still a little bit confused as to why we can't have this on 3000 and 4000 CPU's.... Anyway updated BIOS this morning for my MPG_550_WIFI board, it removed my linux bootloader from the boot list (using windows atm to play CP2077, for now)

Im reposting this for your information: Its not limited on linux only to 5000 series cpu and 6000 series gpu, its only a problem for windows people. On linux as long as 2008 you could find cpus/motherboards/gpus whats supports this, but windows being windows, they never implemented it until this date.

On the latest Beta bios for my ASUS ROG Crosshair VII Hero WIFI, the 4g option is present in the new PCI Subsystem menu, and can be enabled (BIOS version 4001), on Bios 3103 and before the option is not present, and its disabled by default, so no resizable BAR support on them.

AMD Ryzen 7 3800XT
Asus ROG Crosshair VII Hero WiFi
32GB DDR4 3200MHZ
2*AMD VEGA 64
ARCHLINUX Kernel 5.9.12-zen1-1-zen

$ AMD_DEBUG=info glxinfo | grep vram
vram_size = 8192 MB
vram_vis_size = 8176 MB
vram_type = 6
vram_bit_width = 2048
has_dedicated_vram = 1
$ sudo dmesg | grep BAR=
[sudo] password for ******:
[ 2.503440] [drm] Detected VRAM RAM=8176M, BAR=8192M
[ 3.109110] [drm] Detected VRAM RAM=8176M, BAR=8192M

PS: Im pretty sure your Linux Bootloader is still there on your storage device, you just have to look for it in the settings, or add it back into the uefi boot list with two-three uefi command. If its anything that would mess with the bootloader, it would be windows....