[USRP-users] libusb uses only one thread?

Андрій Хома anik123wb at gmail.com
Sun Oct 22 17:09:44 EDT 2017


Hello,
I have:
6 usrp b502mini
The motherboard Z10PE-D16 WS (can it matter in the chipset?)
Intel xeon e5-2430v4 processor
Memory DDR4 1866 (128 GB)

As a result I get overflow ("O") when using 6 usrp at once.
I'm not proficient in profiling, but I saw that only one thread is created
for libusb, maybe this is the bottleneck.

Explanation of attached picture # 1:
1 Create / initialize devices
2 I create two threads for each device, they alternate in the picture:
    one on "recv" (starting from the very first). It can be seen that it is
quite resource intensive, basically time is spent on convert_sc12_item32,
but it's clear that the CPU core copes less
    the second to write to named fifo (those that are more intermittent,
starting with the second). Also is not resource-intensive.
3 I understand that in this thread there lives libusb, and it's only one,
for 6 devices (see picture number 2)

Also, I was playing with usrp x310, and I work quietly with 400Msps (via
dual 10G ethernet), ie convert_sc12_item32 is fully capable of processing
400Msps on one 2.2GHz core, so the bottleneck is the aforementioned single
libusb stream.

Did I make the right conclusions?
If so, then I need to know exactly what CPU power I need, without guessing
on the coffee grounds.
Are there any benchmarks, hardware requirements, so that I can still use
these devices?
[image: Встроенное изображение 1]

[image: Встроенное изображение 2]
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