On 04/02/2015 19:26, Michael Black wrote:
Hi Mike,
> Not sure we want more than 1 thread....my testing shows this on my 8-core box
> since this patch would give me 6 threads.
Agreed, the patch uses a trivially crude algorithm for the FFT thread
count which will use way too many threads on a processor with more than
4 CPUs. In your case that will be 14 threads for FFTs :(
> I think the old improvement >1 thread showed was overtaken by multi-threading
> the top level.
You need to ensure that you run at least one decode in each mode before
running any timing tests. Changing the number of FFT threads requires
new FFT wisdom to be calculated.
You could try:
, "-m", QString::number (qMin (qMax (QThread::idealThreadCount ()
- 2, 1), 2)) //FFTW threads
for line 379 of mainwindow.cpp for a more controlled thread
utilization.That sort of approach will also give sane results for those
who run multiple instances of WSJT-X with multiple RX SDRs.
We need to fine tune the FFT plans with "personalized" thread counts and
perhaps have some user setting to set a maximum number of compute
intensive threads.
>
> Thread 1 2 3 4 5 6
> 4930 1.10 1.27 1.24 1.23 1.29 1.31
> 1.10 1.21 1.25 1.25 1.27 1.31
> 1.09 1.25 1.23 1.22 1.29 1.32
> 1.09 1.22 1.24 1.22 1.27 1.29
> 1.11 1.23 1.22 1.23 1.27 1.33
> 1.12 1.23 1.25 1.27 1.29 1.31
> 1.08 1.22 1.24 1.23 1.26 1.30
> 1.10 1.25 1.23 1.25 1.31 1.30
> 1.14 1.23 1.24 1.26 1.27 1.32
> 1.13 1.22 1.22 1.23 1.28 1.29
> 1.11 1.23 1.25 1.25 1.27 1.32
> 1.12 1.23 1.23 1.24 1.27 1.29
> 1.12 1.25 1.24 1.23 1.27 1.29
> 1.08 1.24 1.25 1.24 1.28 1.34
> 1.08 1.23 1.23 1.21 1.30 1.29
> 1.08 1.27 1.24 1.25 1.28 1.27
> 1.15 1.25 1.25 1.29 1.28 1.30
> 1.13 1.26 1.22 1.27 1.27 1.30
> 1.10 1.25 1.23 1.24 1.27 1.30
> Avg 1.09 1.25 1.24 1.24 1.28 1.30
>
73
Bill
G4WJS.
> -----Original Message-----
> From: Bill Somerville [mailto:g4...@classdesign.com]
> Sent: Wednesday, February 04, 2015 11:02 AM
> To: WSJT software development
> Subject: [wsjt-devel] WSJT-X: Using the latest decoder improvements in WSJT-X
>
> Hi All,
>
> it looks like the latest jt9 using OpenMP and multi-threaded FFTs along with
> Joe's recent re-factorings for performance seem to be approaching stability.
> If anyone wants to try them out on air with WSJT-X, the attached patch will
> allow WSJT-X to be built with them enabled.
>
> Note that the patch enables a fairly lengthy FFT plan optimization and the
> first decode cycle may take a few minutes to complete, do not kill the
> program as the accumulated FFT wisdom is written out at the end of a session.
> Once the FFTW wisdom is saved there will be no further delays.
>
> Testing here results in decodes that are so fast that it hardly seems worth
> looking fro any more performance improvements until we start getting 100's
> concurrent of QSOs per band. Impressive stuff!
>
> Running on a quad-core Core i7 laptop here.
>
> 73
> Bill
> G4WJS.
>
>
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look and join the conversation now. http://goparallel.sourceforge.net/
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