I had the same issues -- the big performance eater in my case was anything
that was doing modulo in a tight loop.
So, if you have something like:
for ( int i = 0; i < 1000; i++) {
array[i % arr_size] = ...
}
You'll take a pretty big hit.
On Wed, Sep 6, 2017 at 4:00 PM, Tom Bereknyei via USRP-users <
usrp-users@lists.ettus.com> wrote:
> We ran into a similar issue. Big things that helped us was to move high
> rate dsp calculations to RFNoC.
>
> I've also had luck with volk_profile. It seems to help with some
> workloads.
> On Wed, Sep 6, 2017 at 16:53 Philip Balister via USRP-users <
> usrp-users@lists.ettus.com> wrote:
>
>> On 09/06/2017 04:38 PM, Marcus Müller via USRP-users wrote:
>> > Hi Mr Hamilton,
>> >
>> > So, what you'd want to optimize first depends on what needs the most
>> > optimization. Your x86 program might be a good place to start looking
>> > into what the bottleneck is. If you're running Linux on your x86, I can
>> > heartily recommend `perf`, which is a tool that lets you display live,
>> > record and analyze the points in your code where the program spends most
>> > time.
>>
>> "perf top" gives results pretty quickly.
>>
>> It also sounds like you aren't using both cpu's to the full extent.
>> Maybe there is just one block doing all the work?
>>
>> Also, looking at using rfnoc to do high rate functions to reduce
>> calculations that need doing on the arm is a good plan.
>>
>> Philip
>>
>> >
>> > In general, modern x86 have way larger memory bandwidth and larger CPU
>> > caches, so that alone can become critical, but also things like more
>> > capable SIMD instructions and less hardware-handling overhead.
>> >
>> > I don't know whether this helped you much, but I hope it's a start,
>> > best regards,
>> >
>> > Marcus Müller
>> >
>> > On 09/06/2017 10:06 PM, S Hamilton via USRP-users wrote:
>> >> We're moving an application that we had running on pc hardware with
>> >> the Ettus B210, to the embedded arm E310. On the pc side we were at
>> >> 80% idle cpu when running (intel i5-4570). With armv7 we're down to
>> >> 30% idle, with one of the cores @100% so it's not keeping up.
>> >> Are there any arm specific optimizations that are recommended or
>> gotchas.
>> >> We are using the release4 version of the SDK and firmware.
>> >>
>> >> We'd also like to use the complex_to_mag_approx RFNOC block. Is there
>> >> any sample code around to look at.
>> >>
>> >> Thanks,
>> >>
>> >>
>> >> _______________________________________________
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>> >
>> >
>> >
>> >
>> > _______________________________________________
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>> >
>>
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> --
> Maj Tom Bereknyei
> Defense Digital Service
> t...@dds.mil
> (571) 225-1630
>
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