Incredibly slow data transfer trought put in Windows vs Linux

Hi,

I'm gettting really surprised with the data troughput I achieved with a
continuous reader on a bulk endpoint compared with the one I have with Linux.

Basicly i'm transfering packets of 34 bytes and i'm getting something like
61KBbytes per second in linux with libusb-1.0

In windows i'm getting only 25 Kbytes per second.

Which can be causing this? Is this normal?

Thanks,

With my best regards,

Nuno

sinosoidal <> wrote:
>
>I'm gettting really surprised with the data troughput I achieved with a
>continuous reader on a bulk endpoint compared with the one I have with Linux.
>
>Basicly i'm transfering packets of 34 bytes and i'm getting something like
>61KBbytes per second in linux with libusb-1.0
>
>In windows i'm getting only 25 Kbytes per second.
>
>Which can be causing this? Is this normal?

What are you using in Windows? WinUSB? Is this a full-speed device? How
many requests are you submitting at once?
--
Tim Roberts,
Providenza & Boekelheide, Inc.

Why don't you use larger transfers? It's not possible to submit more than
one request in a USB frame for the given endpoint, on a UHCI controller. On
OHCIcontroller, it's doable. What controller types you have on your Linux
and WIndows SUTs?

"sinosoidal" <> wrote in message
news:A63B3516-DBE1-425F-9324-...
> Hi,
>
> I'm gettting really surprised with the data troughput I achieved with a
> continuous reader on a bulk endpoint compared with the one I have with
> Linux.
>
> Basicly i'm transfering packets of 34 bytes and i'm getting something like
> 61KBbytes per second in linux with libusb-1.0
>
> In windows i'm getting only 25 Kbytes per second.
>
> Which can be causing this? Is this normal?
>
> Thanks,
>
> With my best regards,
>
> Nuno

Hi Tim,

Thanks for the reply. I have only seen your reply today and i thought no one
was replying. I really appreciate that as this question is really important.

In windows I'm using KMDF with a continuous reader configured for the bulk
endpoint.

The device is full speed and double banked (at90usb1287 from atmel).

I don't know how many requests are being submited because the continuous
reader makes that for me. However I have been messing with the
NumPendingReads parameter of the continuous reader and that doesnt give me
more than 25 Kbytes per second, only less.

Should I use "manual" requests submission to have higher transfer rates?

Thanks,

Nuno

"Tim Roberts" wrote:

> sinosoidal <> wrote:
> >
> >I'm gettting really surprised with the data troughput I achieved with a
> >continuous reader on a bulk endpoint compared with the one I have with Linux.
> >
> >Basicly i'm transfering packets of 34 bytes and i'm getting something like
> >61KBbytes per second in linux with libusb-1.0
> >
> >In windows i'm getting only 25 Kbytes per second.
> >
> >Which can be causing this? Is this normal?
>
> What are you using in Windows? WinUSB? Is this a full-speed device? How
> many requests are you submitting at once?
> --
> Tim Roberts,
> Providenza & Boekelheide, Inc.
> .
>

Hi Alexander,

I'm not using larger transfer for syncing purposes. That doesnt gave me
lower transfer rates on linux, so I supposed that in Windows that isn't a
problem as well.

I believe that the controller is UHCI because in Windows device manager
appears (Universal Host Controller). I'm also submitting two request in my
linux side application based on libusb-1.0

My test machine is the same for the windows and linux versions.

Any tips?

Thanks,

Nuno

"Alexander Grigoriev" wrote:

> Why don't you use larger transfers? It's not possible to submit more than
> one request in a USB frame for the given endpoint, on a UHCI controller. On
> OHCIcontroller, it's doable. What controller types you have on your Linux
> and WIndows SUTs?
>
> "sinosoidal" <> wrote in message
> news:A63B3516-DBE1-425F-9324-...
> > Hi,
> >
> > I'm gettting really surprised with the data troughput I achieved with a
> > continuous reader on a bulk endpoint compared with the one I have with
> > Linux.
> >
> > Basicly i'm transfering packets of 34 bytes and i'm getting something like
> > 61KBbytes per second in linux with libusb-1.0
> >
> > In windows i'm getting only 25 Kbytes per second.
> >
> > Which can be causing this? Is this normal?
> >
> > Thanks,
> >
> > With my best regards,
> >
> > Nuno
>
>
> .
>

There is no latency guarantee in both Linux and Windows. I don't know what
you mean "for syncing purposes" then.

"sinosoidal" <> wrote in message
news:B917121D-23E4-4BA2-93D8-...
> Hi Alexander,
>
> I'm not using larger transfer for syncing purposes. That doesnt gave me
> lower transfer rates on linux, so I supposed that in Windows that isn't a
> problem as well.
>
> I believe that the controller is UHCI because in Windows device manager
> appears (Universal Host Controller). I'm also submitting two request in my
> linux side application based on libusb-1.0
>
> My test machine is the same for the windows and linux versions.
>
> Any tips?
>
> Thanks,
>
> Nuno
>
> "Alexander Grigoriev" wrote:
>
>> Why don't you use larger transfers? It's not possible to submit more than
>> one request in a USB frame for the given endpoint, on a UHCI controller.
>> On
>> OHCIcontroller, it's doable. What controller types you have on your
>> Linux
>> and WIndows SUTs?
>>
>> "sinosoidal" <> wrote in message
>> news:A63B3516-DBE1-425F-9324-...
>> > Hi,
>> >
>> > I'm gettting really surprised with the data troughput I achieved with a
>> > continuous reader on a bulk endpoint compared with the one I have with
>> > Linux.
>> >
>> > Basicly i'm transfering packets of 34 bytes and i'm getting something
>> > like
>> > 61KBbytes per second in linux with libusb-1.0
>> >
>> > In windows i'm getting only 25 Kbytes per second.
>> >
>> > Which can be causing this? Is this normal?
>> >
>> > Thanks,
>> >
>> > With my best regards,
>> >
>> > Nuno
>>
>>
>> .
>>

sinosoidal <> wrote:
>
>I'm not using larger transfer for syncing purposes. That doesnt gave me
>lower transfer rates on linux, so I supposed that in Windows that isn't a
>problem as well.
>
>I believe that the controller is UHCI because in Windows device manager
>appears (Universal Host Controller). I'm also submitting two request in my
>linux side application based on libusb-1.0
>
>My test machine is the same for the windows and linux versions.
>
>Any tips?

Are you specifying 64 bytes per transfer?
--
Tim Roberts,
Providenza & Boekelheide, Inc.