I'm curious to know if the flags do flush denormals on your processor. Forgot to mention that '-O3 -ffast-math' are also set, platform-independent. So if you have a chance to try which flag does something... It's just curiosity.
On Wed, Sep 21, 2016 at 10:34 PM, Christof Ressi <christof.re...@gmx.at> wrote: > Hi Katja, > >> Even if your test reveals a beneficial effect from compiler flags, >> it is better when denormals are detected and flushed in the C code. > > definitely! Maybe using the PD_BIGORSMALL macro on each filter state at the > end of the DSP routine does the trick, just like in all the other recursive > filters in Pd. > > > >> Von: katja <katjavet...@gmail.com> >> An: "Christof Ressi" <christof.re...@gmx.at> >> Cc: pd-list <pd-l...@iem.at>, "Miller Puckette" <m...@ucsd.edu> >> Betreff: Re: [PD] [bob~] denormals issue? >> >> Hi Christof, >> >> Makefile.pdlibbuilder passes flags '-march=pentium4 -msse -msse2 >> -mfpmath=sse' for optimization to the compiler on Windows. You could >> try compiling without (some of) these flags to see if they are >> responsible for the different behavior. Makefile-defined optimization >> flags can be overriden with argument CFLAGS given on command line. >> >> The effect of optimization flags on denormals varies per processor >> type, unfortunately. When we had denormals on Raspberry Pi ARMv6 they >> wouldn't go away no matter what flags, is what I remember. Even if >> your test reveals a beneficial effect from compiler flags, it is >> better when denormals are detected and flushed in the C code. Anyway, >> it is still interesting to know what makes the difference. >> >> Katja >> >> On Wed, Sep 21, 2016 at 12:32 AM, Christof Ressi <christof.re...@gmx.at> >> wrote: >> > Hmmm... I compiled [bob~] myself with MinGW and pd-lib-builder and I >> > noticed two things: >> > 1) the CPU rise is gone >> > 2) it needs only half the CPU. I put 20 [bob~] objects in a switched >> > subpatch and measured the CPU load. The DLL which comes with the Windows >> > binaries needs 15%, while my own DLL needs only 7%! That's quite a deal... >> > >> > Christof >> > >> > PS: I attached the DLL in case you wanna try it yourself. >> > >> > >> >> Gesendet: Samstag, 17. September 2016 um 22:58 Uhr >> >> Von: "Christof Ressi" <christof.re...@gmx.at> >> >> An: pd-l...@iem.at, "Miller Puckette" <m...@ucsd.edu> >> >> Betreff: [PD] [bob~] denormals issue? >> >> >> >> Hi Miller, >> >> >> >> feeding audio into [bob~] and then going to zero will increase the CPU >> >> load by ca. 6%. Clearing the filter or adding a tiny amount of noise >> >> brings the CPU load back to its usual level immediately, so I guess it's >> >> a problem with denormals. >> >> My Pd load meter won't really show the increase, but it's clearly visibly >> >> on Process Explorer. >> >> >> >> See my attached patch. Tried with Pd 0.47.1, Lenovo Thinkpad L440, >> >> Windows 7. >> >> >> >> Christof_______________________________________________ >> >> Pd-list@lists.iem.at mailing list >> >> UNSUBSCRIBE and account-management -> >> >> https://lists.puredata.info/listinfo/pd-list >> >> >> > _______________________________________________ >> > Pd-list@lists.iem.at mailing list >> > UNSUBSCRIBE and account-management -> >> > https://lists.puredata.info/listinfo/pd-list >> > >> _______________________________________________ Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> https://lists.puredata.info/listinfo/pd-list
