Asymmetric USRP throughput

I’m beginning to see some light over my 8MHz tx problems…

the throughput towards my USRP is significantly reduced compared to the
one from it…

./test_usrp_standard_tx
xfered 1.34e+08 bytes in 5.46 seconds. 2.457e+07 bytes/sec. cpu time =
0.492
0 underruns

./test_usrp_standard_rx
xfered 1.34e+08 bytes in 4.19 seconds. 3.2e+07 bytes/sec. cpu time =
0.384
noverruns = 0

what could be the cause for this? any hint…? ( benchmark_usb.py reports
a good throughput up to 32M)

thanks

vincenzo

On Wed, Sep 12, 2007 at 11:55:08PM +0200, Vincenzo P. wrote:

./test_usrp_standard_rx
xfered 1.34e+08 bytes in 4.19 seconds. 3.2e+07 bytes/sec. cpu time = 0.384
noverruns = 0

what could be the cause for this? any hint…? ( benchmark_usb.py reports a good throughput up to 32M)

thanks
vincenzo

What h/w platform are you on?’
What USB host controller do you have?
Is it on a PCI card, or on the motherboard?

$ lspci

Eric

On Thu, Sep 13, 2007 at 02:03:55AM +0200, Vincenzo P. wrote:

AMD sempron 3000+, 512KiB RAM
USB2.0 on board

00:03.0 USB Controller: Silicon Integrated Systems [SiS] USB 1.0
Controller (rev 0f)
00:03.1 USB Controller: Silicon Integrated Systems [SiS] USB 1.0
Controller (rev 0f)
00:03.2 USB Controller: Silicon Integrated Systems [SiS] USB 1.0
Controller (rev 0f)
00:03.3 USB Controller: Silicon Integrated Systems [SiS] USB 2.0
Controller

Vincenzo,

I’m not familiar with this chipset.
It’s not inconceivable that it’s got asymmetric throughput. We’ve
seen that on many PPC host controllers.

Eric

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