Dear Marcus,

Thanks for your help.

I'm tried to understand your advices about interrupt coalescing and I
changed interrupt coalescing options

My default setting like below:

Coalesce parameters for eth0:
Adaptive RX: off  TX: off
stats-block-usecs: 0
sample-interval: 0
pkt-rate-low: 0
pkt-rate-high: 0

rx-usecs: 20
rx-frames: 5
rx-usecs-irq: 0
rx-frames-irq: 0

tx-usecs: 72
tx-frames: 53
tx-usecs-irq: 0
tx-frames-irq: 5

rx-usecs-low: 0
rx-frame-low: 0
tx-usecs-low: 0
tx-frame-low: 0

rx-usecs-high: 0
rx-frame-high: 0
tx-usecs-high: 0
tx-frame-high: 0

I controlled rx-usecs(0 ~ 1000) and rx-frames(0~1000), but I can't change
adaptive-rx or pkt-rate-low(high).

Rx-usecs and rx-frames doesn't help to solve overflow problem.

Did I miss something when control interrupt coalescing ?

What parameters do I have to set ?

Thanks.

2016-03-29 20:52 GMT+09:00 Marcus Müller <[email protected]>:

> Hi SangHyuk,
>
> On 29.03.2016 13:45, SangHyuk Kim wrote:
>
> Hi,
>
> I found two phenomenons when USRP N210 are on receiving mode (but, no
> received data)
>
>
>
> i) When I capture eth0 packets using wireshark, USRP send buffer to host
> continuously. Maybe it is to sampling process.
>
> Of course. How else would the samples from the USRP come to your PC, where
> you put them into GNU Radio??
>
> I think that host cannot read these buffer quickly, so overflow is
> occurred (at high samp_rate).
>
> Yes!
>
>    But, I don't know why host cannot consume these packet quickly (My PC
> CPU : 2.7GHz x 4)
>
> If that is too slow or fast enough depends completely on the application
> you're running. To be honest, 2.7GHz isn't *that* much, if your network
> card doesn't support reducing the number of interrupts sent. Play with
> "interrupt coalescing".
>
>
> ii) If I use samp_rate 25M, CPU utilization is over 300% (But, Tx mode is
> very stable, CPU utilization is under 10% at 25 MSps)
>    I'm using native Ubuntu 14.04 OS, I can't understand these...
>
> Again, CPU usage depends on what you do with the signal, and I don't know
> what "TX mode" is for you.
>
> Best regards,
> Marcus
>
>
>
> Please give me a guide
>
> Thanks.
>
> 2016-03-29 12:50 GMT+09:00 SangHyuk Kim <[email protected]>:
>
>> Hi,
>>
>> I tried to change recv_buffer_size, but I can't find where I input buffer
>> size.
>>
>> What is the default recv_buffer_size ?
>>
>> And why Tx is ok at BW 25MHz but Rx is not at same bandwidth ?
>>
>> Thanks
>>
>> 2016-03-28 10:06 GMT+09:00 Marcus D. Leech < <[email protected]>
>> [email protected]>:
>>
>>> On 03/27/2016 09:01 PM, SangHyuk Kim wrote:
>>>
>>> Hi,
>>>
>>> My Ethernet controller info.
>>>
>>> Ethernet controller: Broadcom Corporation NetXtreme BCM57762 Gigabit
>>> Ethernet PCIe
>>> Subsystem: Apple Inc. Device 00f6
>>> Physical Slot: 9
>>> Flags: bus master, fast devsel, latency 0, IRQ 19
>>> Memory at acb00000 (64-bit, prefetchable) [size=64K]
>>> Memory at acb10000 (64-bit, prefetchable) [size=64K]
>>> Expansion ROM at a0a00000 [disabled] [size=64K]
>>> Capabilities: <access denied>
>>> Kernel driver in use: tg3
>>>
>>> And I changed rmem_max and wmem_max but, it was not effect.
>>>
>>> How can I change recv_buffer_size ??
>>>
>>> Thanks
>>>
>>> Just specify it in the device arguments.
>>>
>>> recv_buffer_size=<some_value>
>>>
>>> In your device arguments
>>>
>>>
>>>
>>>
>>> 2016-03-28 0:37 GMT+09:00 Marcus D. Leech < <[email protected]>
>>> [email protected]>:
>>>
>>>> On 03/27/2016 05:53 AM, tom x wrote:
>>>>
>>>> Hi,
>>>>
>>>> >I think my PC can handle this sample rate
>>>> Have you tried other rates? What's the highest sample rate before
>>>> overflow occurs?
>>>>
>>>> >How can I handle this problem ?
>>>> Maybe a power squelch block? You can filter out signals that don't meet
>>>> a db threshold before they reach your PC.
>>>>
>>>> <https://gnuradio.org/doc/doxygen/classgr_1_1analog_1_1pwr__squelch__cc.html>
>>>> https://gnuradio.org/doc/doxygen/classgr_1_1analog_1_1pwr__squelch__cc.html
>>>>
>>>> That's not how Gnu Radio works.    The blocks run on your PC.
>>>>
>>>> However the power squelch I believe interrupts the sample stream, so
>>>> that if you're writing to disk, the average write rate to the disk
>>>>   is lowered in this case, depending on the dynamics of the amplitude
>>>> of your signals, since you'll only be writing "good stuff".
>>>>
>>>> If you're getting 'D', this may be your ethernet controller--what type
>>>> do you have?  The 82579LM is notorious for dropping data.
>>>>   Also, make certain that your network buffering is configured
>>>> correctly.  See the notes here:
>>>>
>>>> http://files.ettus.com/manual/page_transport.html#transport_udp_linux
>>>>
>>>>
>>>>
>>>>
>>>> On Sun, Mar 27, 2016 at 10:56 AM, SangHyuk Kim < <[email protected]>
>>>> [email protected]> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I'm using USRP N210 with CBX daughter board on native Ubuntu 14.04
>>>>>
>>>>> When I open fft_uhd with sample rate about 25 MSps, it spits out of
>>>>> "D"(overfow)
>>>>>
>>>>> As I know, USRP N210 support sample rate up to 25 MSps and it's
>>>>> possible on Tx mode.
>>>>>
>>>>> I think my PC can handle this sample rate, but I don't know why this
>>>>> is happened.
>>>>>
>>>>> How can I handle this problem ?
>>>>>
>>>>> Thanks.
>>>>>
>>>>> _______________________________________________
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>>>>>
>>>>>
>>>>
>>>>
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>>>
>>
>
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