Nvidia DU-07764-001 User manual

DU-07764-001 | September 2015
User Guide
GPUMODESWITCH

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DOCUMENT CHANGE HISTORY
DU-07764-001
Version
Date
Authors
Description of Change
1.0
8/30/2015
AC
Initial release

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Chapter 1. Introduction.................................................................................. 1
1.1 Compute and graphics mode ........................................................................ 1
1.2 When to use graphics mode ......................................................................... 2
1.3 Supported products ................................................................................... 3
Chapter 2. Using gpumodeswitch .................................................................... 4
2.1 Supported environments ............................................................................. 4
2.2What’s in the package ................................................................................ 4
2.3 Running gpumodeswitch ............................................................................. 5
2.3.1 Listing current GPU modes................................................................... 5
2.3.2 Switching GPU modes ........................................................................ 6
2.4 Linux bootable images ................................................................................ 9
2.4.1 Booting directly from ISO ...................................................................10
2.4.2 Booting from a USB flash key ..............................................................10
2.5 Troubleshooting.......................................................................................12
2.5.1 Unloading an existing NVIDIA driver ......................................................12

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LIST OF FIGURES
Figure 1 Connecting gpumodeswitch.iso via server remote management................. 10
Figure 2 Launching an administrator command prompt ..................................... 11
LIST OF TABLES
Table 1 Compute mode settings ................................................................. 1
Table 2 Graphics mode settings.................................................................. 2

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Chapter 1. INTRODUCTION
gpumodeswitch is a command-line tool that is used to switch supported NVIDIA GPUs
between compute and graphics mode. This chapter describes these modes and when to
use them. Chapter 2 describes how to use gpumodeswitch.
1.1 COMPUTE AND GRAPHICS MODE
NVIDIA Tesla GPUs are shipped in a configuration optimized for high-performance
compute (HPC) applications:
Setting
Value
Notes
Classcode
3D Controller
This classcode indicates to operating systems (OS) that the GPU is not
intended for use as a primary display device.
Memory BAR
8 gigabytes
Tesla GPUs expose a large memory base address register (BAR) for direct
access to the framebuffer from the CPU, and other PCI Express devices.
I/O base BAR
Disabled
The GPU need not consume any legacy I/O resources when used as a non-
display device.
ECC protection
Enabled
Error Correcting Code (ECC) is enabled on the GPU framebuffer to protect
against single- and multi-bit memory errors.
Table 1 Compute mode settings
Collectively this GPU configuration is referred to as compute mode. While compute mode
is optimal for HPC usage, it can cause compatibility problems with OS and hypervisors
when the GPU is used primarily as a graphics device:
Some OS require that the GPU advertise a VGA display controller classcode in order
for the GPU to be used as a primary graphics device.

Introduction
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Some hypervisors cannot support passthrough of GPUs with large memory BARs to
guest virtual machines.
To address these problems, certain NVIDIA Tesla GPUs support setting the GPU into
graphics mode:
Setting
Value
Notes
Classcode
VGA Controller
This classcode indicates to OS that the GPU can function as a primary
display device.
Memory BAR
256 megabytes
The GPUs a smaller memory BAR for direct access to the framebuffer.
I/O base BAR
Enabled
The GPU exposes an I/O BAR to claim the resources require to operate as
a VGA controller.
ECC protection
Disabled
ECC protection is disabled by default, though it can still be enabled by
use of the nvidia-smi management tool
Table 2 Graphics mode settings
The mode of the GPU is established directly at power-on, from settings stored in the
GPU’s non-volatile memory. gpumodeswitch is used to program the mode of the GPU
by updating the GPU’s non-volatile memory settings.
1.2 WHEN TO USE GRAPHICS MODE
We recommend that graphics mode be used whenever supported Tesla products are
used in the following scenarios:
GPU passthrough with hypervisors that do not support large BARs. At the time of
publication, this includes Citrix XenServer 6.2, 6.5, VMware ESXi 5.1, 5.5, 6.0, Red Hat
Enterprise Linux 7.0, 7.1.
GPU passthrough to Windows VMs on Xen and KVM hypervisors.
GRID Virtual GPU deployments.
VMware vSGA deployments.

Note: consult individual NVIDIA product release notes for the latest information on
compatibility with compute and graphics modes.

Introduction
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1.3 SUPPORTED PRODUCTS
At the time of writing, gpumodeswitch is supported on the following products:
Tesla M60
Tesla M6

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Chapter 2. USING GPUMODESWITCH
gpumodeswitch is a command line utility that runs on Windows or Linux. This chapter
describes how to to use gpumodeswitch, and the optional Linux boot packages included
with gpumodeswitch.
2.1 SUPPORTED ENVIRONMENTS
gpumodeswitch can be run in the following environments
Windows 64-bit command prompt
Linux 32/64-bit shell (including Citrix XenServer dom0)

Note: If the server platform hosting the Tesla GPUs does not natively run any of
the supported environments, we recommend temporarily booting Linux on the
server; the gpumodeswitch release package includes bootable Linux images for
this purpose. These images are described in section 2.4.
2.2 WHAT’S IN THE PACKAGE
File
Description
gpumodeswitch.exe
Windows executable
nvflsh64.sys
Windows 64-bit driver module
gpumodeswitch
Linux executable, also usable on XenServer dom0
gpumodeswitch.iso
Bootable Linux ISO image
gpumodeswitch.zip
Bootable Linux image for use with USB storage (e.g. a flash key)

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2.3 RUNNING GPUMODESWITCH
gpumodeswitch supports two operations: listing the current mode of GPUs in the
platform, and changing the mode of individual or all GPUs.
When running on Linux, gpumodeswitch requires root permissions.
When running on Windows, gpumodeswitch requires administrator permissions (see
Figure 2 on page 11), and the nvflsh64.sys driver should be in the same directory as
the gpumodeswitch executable.
2.3.1 Listing current GPU modes
To list the current mode of all GPUs in the system, use --listgpumodes:
# gpumodeswitch --listgpumodes
NVIDIA GPU Mode Switch Utility Version 1.02
Copyright (C) 2015, NVIDIA Corporation. All Rights Reserved.
PLX (8747h) (10B5,8747,10B5,8747) H:--:NRM S:00,B:81,PCI,D:00,F:00
Adapter: PLX (8747h) (10B5,8747,10B5,8747) H:--:NRM S:00,B:81,PCI,D:00,F:00
Identifying EEPROM...
EEPROM ID (47,8747) : uChip 25AA320A 1.8-5.5V 4Kx8S, page
GPU Mode: N/A
Tesla M60 (10DE,13F2,10DE,113A) H:82:SP8 S:00,B:83,PCI,D:00,F:00
Adapter: Tesla M60 (10DE,13F2,10DE,113A) H:82:SP8 S:00,B:83,PCI,D:00,F:00
Identifying EEPROM...
EEPROM ID (EF,3013) : WBond W25X40A 2.7-3.6V 4096Kx1S, page
GPU Mode: Graphics
Tesla M60 (10DE,13F2,10DE,113A) H:82:SP16 S:00,B:84,PCI,D:00,F:00
Adapter: Tesla M60 (10DE,13F2,10DE,113A) H:82:SP16 S:00,B:84,PCI,D:00,F:00
Identifying EEPROM...
EEPROM ID (EF,3013) : WBond W25X40A 2.7-3.6V 4096Kx1S, page
GPU Mode: Compute
#
2.3.1.1 Log file output
The --listgpumode command also writes GPU mode information to a log file named
listgpumodes.txt. By default gpumodeswitch creates the log file in the current

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working directory (if the current working directory is writable). To change the path on
which the log file is written, use the --outfilepath option:
# gpumodeswitch --listgpumodes --outfilepath /tmp/

Note: when using the bundled Linux bootable images (see section 2.4), the system
boots into a read-only file system. Log files can be generated by using the
outfilepath option to write the log files into /tmp.
The log file summarizes GPU modes:
# more /tmp/listgpumodes.txt
GPU ID:
PLX (8747h) (10B5,8747,10B5,8747) H:--:NRM S:00,B:81,PCI,D:00,F:00
GPU Mode: N/A
GPU ID:
Tesla M60 (10DE,13F2,10DE,113A) H:82:SP8 S:00,B:83,PCI,D:00,F:00
GPU Mode: Graphics
GPU ID:
Tesla M60 (10DE,13F2,10DE,113A) H:82:SP16 S:00,B:84,PCI,D:00,F:00
GPU Mode: Graphics
#
2.3.2 Switching GPU modes
To switch a GPU’s mode, use the --gpumode command: --gpumode graphics switches
to graphics mode, --gpumode compute switches to compute mode.
2.3.2.1 Switching all GPUs
By default, the command works on all supported GPUs in the platform; confirm the
mode switch by entering ‘y’:
# gpumodeswitch --gpumode graphics
NVIDIA GPU Mode Switch Utility Version 1.02
Copyright (C) 2015, NVIDIA Corporation. All Rights Reserved.
Update GPU Mode of all adapters to "graphics"?
Press 'y' to confirm or 'n' to choose adapters or any other key to abort:
y
Updating GPU Mode of all eligible adapters to "graphics"
PLX (8747h) (10B5,8747,10B5,8747) H:--:NRM S:00,B:81,PCI,D:00,F:00
Adapter: PLX (8747h) (10B5,8747,10B5,8747) H:--:NRM S:00,B:81,PCI,D:00,F:00
Identifying EEPROM...
EEPROM ID (47,8747) : uChip 25AA320A 1.8-5.5V 4Kx8S, page
Cannot set GPU mode for this adapter