Low sample rate

[Ducie54]

Any idea why the software sample rate is so dam slow. Not sure if it is a usb driver issue or a limitation of the ECU. Sample rate goes between 40 and 25Hz. worst when logging.

 

[/IMG]

[TechDave]

If I remember correctly it's bound to the rate at which the USB returns data from the ecu, we send a data request to the ecu, it fires back a huge packet of data, we use the new data to draw, then we repeat.

So the size and rate of the data retrieve is the limiting factor on G4+ for the rate, which ought to be about 65Hz, you can't really do much to speed this up because you're physically bound by the connection speed and size of the data packet.

When you log, there are a bunch of extra functions going on, saving all your data to memory, and the drawing functions become more intense, this increases the time between data retrieval and the request for new data.

In my experience, drawing the screen wasn't really a major contributor to rate, but it has been a few years since I clocked all of it.

This is high on my hit list for G4X.

[Adamw]

3 minutes ago, TechDave said:

If I remember correctly it's bound to the rate at which the USB returns data from the ecu, we send a data request to the ecu, it fires back a huge packet of data, we use the new data to draw, then we repeat.

So the size and rate of the data retrieve is the limiting factor on G4+ for the rate, which ought to be about 65Hz, you can't really do much to speed this up because you're physically bound by the connection speed and size of the data packet.

When you log, there are a bunch of extra functions going on, saving all your data to memory, and the drawing functions become more intense, this increases the time between data retrieval and the request for new data.

In my experience, drawing the screen wasn't really a major contributor to rate, but it has been a few years since I clocked all of it.

This is high on my hit list for G4X.

He should see better than 25Hz though shouldn’t he?  I have the pc logger running in the background the whole day when I’m tuning with all parameters logged and I normally see about 55Hz.  It might drop to 50 when I’m doing a store. My laptop is nothing special.

 I know Nigel has quite a bit going on in his tune, would the ecu processor load have any influence on PC link speed?

[TechDave]

24 minutes ago, Adamw said:

 I know Nigel has quite a bit going on in his tune, would the ecu processor load have any influence on PC link speed?

...possibly? I never touched the firmware.

I'll have a go at bench testing that in the new year, unless you already have a sim and some spare time?

@Ducie54 if you go to device manager, right click on the Link drivers, then go to settings or properties or something, there's some stuff in there about the buffer size? Sorry it's a bit vague, I'm not in the office at the moment, otherwise I'd fire in a screenshot.

[Adamw]

8 minutes ago, TechDave said:

unless you already have a sim and some spare time?

I’m at Disneyland in Hong Kong, didn’t think I’d need the sim today. Lol.

[Ducie54]

Thanks for the quick response guys. PC im now using is a ASUS ROG scar strix 3 with the RTX 2060 so should have no issues there. Hope the below pic helps. Also happy for anyone to remote logon and have a play around.

Not sure it it makes a difference but i have both CAN 1 and 2 channels full.

 

[/IMG]

1 hour ago, Adamw said:

I’m at Disneyland in Hong Kong, didn’t think I’d need the sim today. Lol.

Enjoy your holidays, this can wait as its not urgent just annoying.

[Ducie54]

So i think think might be because this dam PC keeps using the Intel graphics instead of the geforce GPU. No idea how to stop that atm.

[Ducie54]

So after fixing that im now at 60hz and dropping down to 31hz when logging. Still pretty poor tho. If i change the logging rate from 40hz to 20hz the sample rate increases to 43hz. 

Is that a ECU limitation? 

[wastegate]

Is 9600 baud normal? I looked the Link USB Com port settings on my laptop and it's 115200 by default, but I'm not currently connected actively to a ECU at the moment and about an ocean away from one.

In regards to Integrated graphics vs the geforce gpu, in my experience it doesn't really make a difference. The Intel integrated is a pretty good gpu for what PCLink ask of it. But if you want, you can change the affinity for PClink by going into NVidia Control Panel, then Manage 3D Settings, Program Settings then choose PCLink or Add it if it's not there and you can choose which GPU to use for it.

 

[Ducie54]

2 hours ago, wastegate said:

Is 9600 baud normal? I looked the Link USB Com port settings on my laptop and it's 115200 by default, but I'm not currently connected actively to a ECU at the moment and about an ocean away from one.

In regards to Integrated graphics vs the geforce gpu, in my experience it doesn't really make a difference. The Intel integrated is a pretty good gpu for what PCLink ask of it. But if you want, you can change the affinity for PClink by going into NVidia Control Panel, then Manage 3D Settings, Program Settings then choose PCLink or Add it if it's not there and you can choose which GPU to use for it.

 

Not sure if 9600 normal, will try 115200 cheers.

 

[TechDave]

On 12/31/2019 at 10:28 AM, Adamw said:

 I know Nigel has quite a bit going on in his tune, would the ecu processor load have any influence on PC link speed?

On 12/31/2019 at 11:02 AM, TechDave said:

...possibly? I never touched the firmware.

I'll have a go at bench testing that in the new year, unless you already have a sim and some spare time?

@Ducie54 if you go to device manager, right click on the Link drivers, then go to settings or properties or something, there's some stuff in there about the buffer size? Sorry it's a bit vague, I'm not in the office at the moment, otherwise I'd fire in a screenshot.

I've been thinking about this.

The ECU doesn't know you're PC Logging, it doesn't do anything differently when you press F8, therefore the issue must be in PCLink, memory access or the drawing.