On Thu, Sep 22, 2011 at 1:41 AM, Achilleas Anastasopoulos <anas...@umich.edu> wrote: > I am comparing the following 2 systems on GRC: > > [source] --> [block A] --> [sink] > > and > > [source] --> [block A] -->[sink] > |___________________^ > > where [block A] is a very CPU-intensive SP block, source and sink are > very simple SP blocks, > and neither source nor sink set the sample rate, neither do i have any > throttle in the graph (intentionally). > > When I run the first configuration on a 2-core machine > I get 2 CPU traces that alternate between 100% and 20% > for large chunks of time which means that the thread that is running > A overwhelms the system. > > So far so good. > > When I run the second configuraiton i get 2 CPU traces that alternate > around a load of > 65% without any of them touching 100% (except occasionally) which seems like a > more "normal" situation. > > So I have 2 questions: > > 1) why is it that the system does not "crash" even in the absense of a > throttle? > 2) why is it that the 2nd configuration results in a lower overall load?
Then I guess that your sink is getting twice the amount of data in the second graph. As the sink is now slower tahn source, it drives the pipeline. Then your block A gets samples at half rate. First graph is 100%+20% = 120%. If block A uses all CPU power, then the second graph should use around 120% / 2 = 60%. Does it makes sense? Pascal _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
