Unlock FP/BF16 instruction issue rate on Nvidia 3000's cards to their professional equivalents
This Linux kernel module combines the CMP unlocker's V67/PLM technique with the pre-driver timing of the UEFI approach. It runs the unlock, writes the speed selectors (SS0 0x88888888
, which selects the full BF16 rate, and the 4-bit SS1 0x8
IMLA4) and performs FLR before the unmodified NVIDIA driver binds the card. It is neither a UEFI application nor a patched NVIDIA driver.
The benefit of this early kmod driver is that it does not require manual patching each time nvidia releases a new driver version.
The effect of this unlock is that it doubles the instruction issuing speed of FP/BF16 FMA into FP32 operations on GA102, GA103, GA104 and GA106 cards.
3090 Ti dense 8192³ GEMM at 450 W, five-sample medians with FP32 accumulation:
Input | Before | After |
---|---|---|
FP16 | 87.46 TFLOPS | 118.39 TFLOPS |
BF16 | 87.50 TFLOPS | 157.41 TFLOPS |
TF32 | 42.58 TFLOPS | 82.61 TFLOPS |
First run:
git clone https://github.com/Zagitta/gpu-unlock
cd gpu-unlock
make install
Then append gpu_unlock.targets=all
to your kernel command line, keeping
existing options:
- GRUB (Debian/Ubuntu/Mint): add it inside
GRUB_CMDLINE_LINUX_DEFAULT
in/etc/default/grub
, then runsudo update-grub
. - GRUB (Arch/CachyOS): same edit, then run
sudo grub-mkconfig -o /boot/grub/grub.cfg
. - Fedora/RHEL: run
sudo grubby --update-kernel=ALL --args="gpu_unlock.targets=all"
. - systemd-boot: append it to the
options
line in your boot entry (bootctl status
shows its location). - UKI / generated entries: add it to
/etc/kernel/cmdline
and regenerate your boot images/entries (e.g.sudo mkinitcpio -P
for mkinitcpio UKIs).
Every build downloads the pinned NVIDIA/CachyOS inputs over HTTPS, checks
their SHA-256, and generates firmware only in the build directory and the
binary package. All three formats install through the same make install-*
targets. Packages are built from the committed HEAD
.
Build, install build dependencies, and install the packages in one step (asks for your sudo password):
make install # detect the distribution and select an installer
make install-arch # makepkg -sif
make install-deb # apt-get build-dep, dpkg-buildpackage, apt-get install
make install-rpm # dnf builddep, rpmbuild, dnf install
make install
uses /etc/os-release
(ID
, then ID_LIKE
) to detect Arch,
Debian/Ubuntu, or Fedora/RHEL/CentOS families. The RPM installer requires DNF.
For other distributions, select a compatible explicit target above.
make arch
, make deb
and make rpm
only build. Debian and RPM packages go
to build/deb
and build/rpm
. The NVIDIA inputs are cached in
~/.cache/gpu-unlock/inputs
(make inputs
; override with INPUTS=
).
dpkg-buildpackage
itself never uses the network, so a clean-chroot build (sbuild or
pbuilder) needs GPU_UNLOCK_INPUTS
pointing at that cache.
The make dist
archive, the Debian source package and the .nosrc.rpm
contain no NVIDIA archives or generated firmware.
The packages put gpu_unlock
and its firmware in the initramfs and load it
there, before nvidia
can bind a card:
- mkinitcpio:
/etc/mkinitcpio.conf.d/zz-gpu-unlock.conf
insertsgpu_unlock
right beforenvidia
inMODULES
, so a display card is blank for as short a time as possible. Withoutnvidia
in the image, it goes last and still runs before annvidia
loaded from the root filesystem. Images are rebuilt on install. mkinitcpio ignores drop-ins for an image built with-c <config>
or a preset_config
; putgpu_unlock
right beforenvidia
in that config'sMODULES
yourself. - initramfs-tools:
/usr/share/initramfs-tools/modules.d/gpu-unlock.conf
. - dracut:
/usr/lib/dracut/dracut.conf.d/gpu-unlock.conf
.
With initramfs-tools and dracut, the module is built for every installed kernel that has headers, and those kernels' images are rebuilt on install and again on removal. Kernels installed later get the module and a new image from the kernel's own install hooks.
There is no softdep nvidia pre:
rule: kmod honours only the first
softdep nvidia
line it reads, so other packages' rules (nvidia-utils
,
gddr6_hwmon
) would silently override it, or it would override theirs.
The module does nothing unless the kernel command line opts in:
gpu_unlock.targets=all # every unbound GA102/GA103/GA104/GA106 card
gpu_unlock.targets=0000:21:00.0 # only these cards
gpu_unlock.targets=0000:21:00.0,0000:22:00.0 # comma-separated
Addresses are full PCI names as lspci -D
prints them (hex digits in either
case), independent of GPU numbering and display role. An entry that is not
a GA102/GA103/GA104/GA106 card, including all
mixed with addresses, is logged and ignored.
The cards are unlocked concurrently, about a second in all however many
there are, and each on its own: a card that is already bound or powered
down is skipped. Bus mastering that the board firmware left on (Supermicro
X11 does this whatever its option ROM and bus master settings) is cleared
first; a card some driver already initialised is still refused. Then
nvidia
loads and binds every card as usual.
The display card works too. Its firmware framebuffer (the boot console and
Plymouth) keeps running while the unlock's firmware steps run, and is
removed just before the card's reset, as nvidia-drm
would do a moment
later anyway. Its screen is blank from that reset until nvidia-drm
takes
over.
Loading the module by hand after boot does nothing to a card that nvidia
has bound.
Suspend to RAM powers the cards off, which resets the speed selectors. After
resume the module unlocks every card it unlocked at boot again, before
nvidia
resumes it: its suspend notifier runs just ahead of the one nvidia
resumes its cards from (NVreg_UseKernelSuspendNotifiers=1
, the default in
current drivers; nvidia-resume.service
runs later still). This adds about a
second to resume. A card that kept power, as in suspend to idle, is still
unlocked and is only read. A card that nvidia
has already resumed, or that is
bound to another driver, is left as it is, and the log says why. Add
gpu_unlock.resume=0
to the kernel command line, or write 0
to
/sys/module/gpu_unlock/parameters/resume
, to turn this off. Hibernation is
not covered.
Check the result with:
journalctl -k -b | grep gpu_unlock
lspci -nnk -s 0000:21:00.0
To stop unlocking, remove gpu_unlock.targets=
from the kernel command line;
for a one-off boot, delete it in the bootloader's edit screen. Removing the
packages also removes the module and the initramfs drop-ins.
If the firmware on a card never stops, the module logs it and keeps the DMA buffers that firmware may still use until the next power off. Power off before trying again.
The kernel module and local packaging are GPL-2.0-only. The generated payload
derives from the pinned CMP reference; NVIDIA firmware remains under its own
terms. See firmware/NOTICE.md
and licenses/
for attribution and notices.
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