Maximum Number of Process Calculations
The NumProcesses parameter is the number of user space processes per service within the [xxxx] section domain with access to this Intel® QAT Endpoint.
The value to which this parameter can be set is determined by a number of factors including the number of cryptography instances and/or data
compression instances in the process section along with ServicesEnabled and potentially ServicesProfile. The total number of processes, per service,
created by the driver is given by the expression (e.g., for cryptography):
(NumProcesses) x (NumberCyInstances)
The maximum number of processes that can be supported is dependant upon the underlying hardware.
Increasing the Maximum Number of Processes/Instances
Note
One bank is used per Intel® QAT virtual function (VF).
This section only applies when the instances that make use of polled mode.
The maximum number of instances can be increased with the careful selection of the ServiceEnabled parameter.
Compression, symmetric cryptography, and asymmetric cryptography each require two rings out of the 16 possible rings for a ring bank. By selecting only, the services needed, the number of instances can be increased.
Here are the variations including the maximum number of processes that can be supported for given configuration:
Note
The ServicesProfile parameter value may also need to be changed. See Services Profile for additional information.
ServicesEnabled |
QAT 1.7x |
QAT 2.0 |
Notes |
|---|---|---|---|
|
128 |
64 |
Compression and asymmetric crypto service not available. |
|
128 |
64 |
Compression and symmetric crypto service not available. |
|
128 |
Invalid |
Compression and symmetric crypto service not available. |
|
128 |
64 |
Asymmetric and symmetric crypto service not available. |
|
64 |
32 |
Asymmetric crypto services will not be available. |
|
64 |
32 |
Symmetric crypto services will not be available. |
|
Invalid |
32 |
Compression services will not be available. |
Invalid Configurations
If maximum number of processes is exceeded, the acceleration software will fail to load. The error message will be similar to:
service qat_service restart qat_dev0
Stopping device qat_dev0
Starting device qat_dev0
Processing /etc/4xxx_dev0.conf
Ioctl failed
QAT Error: Failed to load config data to device
And dmesg output will look similar to:
[116378.383041] Don't have enough rings for instance SSL0 in process SHIM_DEV0_INT_32
[116378.391976] 4xxx 0000:6b:00.0: Failed to create rings for cy
[116378.398881] 4xxx 0000:6b:00.0: Failed to process user section SHIM
[116378.406484] 4xxx 0000:6b:00.0: Failed to config device
Configuring Instances for Virtual Functions
To configure the number of instances for a virtual function:
Install the driver package on the host with SR-IOV enabled.
Update the physical function configuration file to set
ServicesEnabled(refer to Increasing the Maximum Number of Processes/Instances).Perform
qat_service shutdownandqat_service start.Update the virtual function configuration file to set
ServicesEnabled(refer to Increasing the Maximum Number of Processes/Instances).Restart the
qat_service.
The value of ServicesEnabled in the VF configuration file should be the same as the value of ServicesEnabled in the PF configuration file,
or a subset of that value as shown in this table. For instance, if a PF is configured as cy, allowable VF configurations related to that PF can
only be cy, asym, or sym. VF device restart will fail if a VF configuration is not allowed for that related PF.
If a VF service is configured to a subset of PF service, the number of VF instances is limited to the number allowed for that PF service as described
in Increasing the Maximum Number of Processes/Instances. For example, if the PF configuration file has
ServicesEnabled=dc;asym, only four (not eight) dc instances are enabled if the VF is configured for dc only.
Note
Valid Physical Function for each supported platform is described in the Configuration Variations table.
Configured PF Service |
Available VF Services |
|---|---|
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