PEAK-System Forum

Hello,

in the Linux driver (pcanfd_pci.c) there are kernel module options fdirqcl (count_limit) and fdirqtl (time_limit) which allow configuration of interrupt throttling and therefore latency vs. throughput tuning.

Are these parameters configurable in a Windows environment with the driver pcan_pci.sys?
Are there similar parameters for the pcan_usb.sys driver?

Kind Regards,
Martin

Dear Martin,

no, these parameters are not included (and also not necessary) in the pcan_pci.sys driver but in one of the next driver versions such a feature will be implemented inside our Windows USB driver.

regards

Hello,

OK, as the count_limit and the time_limit are actually values inside registers of the PCI hardware to control the rate of interrupts I was thinking that the PCI driver can set those in the same way the Linux driver does.

Regarding the Windows USB driver I am looking forward to the new version.

I guess your are you pointing to the fast_fwd (Fast Forward) Feature of the USB hardware the Linux driver is capable of activating. Am I right?

Kind regards,
Martin

Hi,

do you have any performance problems with our PCIe Windows driver or what´s the reason for your question?

Hello,

No, I have no performance issues with the Windows PCIe driver as we are not using PCIe hardware currently, but we are investigating how to improve the latency with the Windows USB driver and hardware.

Therefore we evaluated die PCIe and USB hardware in a Linux environment and found out, that the mentioned parameters (fdirqcl, fdirqtl and fast_fwd) reduce the latency of received CAN messages on both types of hardware by a factor of 10 for PCIe and a factor 5 for USB.

Therefore my question whether further reduction of latency is possible in the Windows drivers (regarding the USB hardware).

King Regards,
Martin

Hi,

as already written in a previous post: In one of the next driver versions such a feature will be implemented inside our Windows USB driver.
Unfortunately i can´t tell you any time line for this at the moment.

Hello again,

It now says at https://www.peak-system.com/CAN-Geraete ... 403.0.html:

The "Fast Forward" feature is now available for PCAN-USB Classic devices

Is it also supported for the PCAN-USB X6?
Can (and if yes, how) the feature be activated via CANAPI4?

Kind Regards,
Martin

Hi,

yes, all PCAN FD hardware supports that feature. See parameter CAN_PARAM_IRQ_TIMING in the PCAN-Developer 4 documentation for more details

regards

Michael