Agreed :)

On 28.08.2015 18:16, Jeon wrote:
> Daer Marcus,
>
> Thank you for your detailed answer. Now I feel I am getting to it...
> But, not fully, yet :)
>
> What I've said 'one' in the previous post is, you can understand with
> the figure:
> http://i.imgur.com/QG5uryH.png
> I've posted the same figure in another thread some days ago.
>
> Anyway, 'one' I meant is, the total sum of percent runtime. That is
> one and should be.
>
> Regards,
> Jeon.
>
>
>
> 2015-08-27 2:09 GMT+09:00 Marcus Müller <[email protected]
> <mailto:[email protected]>>:
>
>     Hi Jeon,
>>     But I don't think that GNU Radio uses 100 percent (= one) of CPU
>>     capability.
>     Well, that obviously depends on what you /do /with GNU Radio.
>     Generally, GNU Radio scales pretty well, so I'm going to reply with:
>     GNU Radio tries to consume as much CPU as possible. There's
>     limiting factors, mainly RAM access and IO that limit how much CPU
>     can get consumed.
>
>     As you seem to be running a receiver: There's the upper limit on
>     how much CPU can get used of samples coming in. You can only
>     process as much signal as there is. Also, things that are out of
>     the scope of the GNU Radio process tend to play an important rule
>     here: The kernel has to talk to your radio hardware, etc.
>
>     I'm not quite sure what you refer to with "one"; do you mean the 1
>     that tools like "top" would display (namely: one fully occupied
>     CPU core according to a more or less useful statistic; single
>     processes can in that metric actually have CPU loads > 1)?
>
>>     In order to calculate runtime usage of each block, therefore, it
>>     can be done by multiplying usage of GNU Radio process.
>     No. GNU Radio is a heavily multi-threaded architecture, so each
>     block runs in its own thread. Assuming you have a multi-core CPU,
>     multiple threads will run at once; one core of your CPU might be
>     100% occupied by the GNU Radio block thread(s) running on it,
>     whereas another is only 80% busy etc. This does not allow direct
>     mapping of "percentage of CPU load" to actual time.
>
>     However, the performance counters offer exactly what you seem to
>     need: The percentages your looking at are computed from the
>     microseconds that each block spends in its work function. So just
>     look at these total times.
>
>     I think it would be interesting to hear what you want to do, maybe
>     we have an idea how to measure what is of interest to you.
>
>     Best regards,
>     Marcus
>
>
>
>
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