[Csnd] opcodes that minimize cpu usage for older machines?

Is there any good list (or rules of thumb) as to which opcodes will be easiest on cpu (Or conversely, which are more likely to balk) where one is playing many overlapping notes?

Forrest Curo
San Diego

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Apr 23 2022, Forrest Curo has written:

Is there any good list (or rules of thumb) as to which opcodes will be
easiest on cpu

Not to my knowledge. There are few opcode families, which are designed
to scale quality and thus PU usage, i.e. adsynt and adsynt2 or mvclpf1
to mvclpf4 .

There is cpumeter to help further.

As a rule, I'd say more audio rate operations opposed to control rate
incrase usage. In table morphing/mutiplying smaller tables help. But
that's most empirical and I am not a daily Csound power user, so take
that with a pinch of salt.

Hope that helps for a start.

Best wishes,


Thanks; it does help!

One test might be to churn out multiple simultaneous instances of an instrument, seeing how the cpumeter you mention behaves. (Or how many xruns pop up when I increase the numbers?)

Jeanette and Forest,

Sadly, the cpumeter opcode does not work on Mac or Windows Csound only Linux. We need one for the Mac,
or maybe one that runs in Cabbage? or one that runs in CsoundQt?

It seems that the cpuprc opcode does run on the mac, but it is more like maxalloc - to make sure things don’t overload the system.

When checking things, I often use the clockon and clockoff opcodes

But, I think it would be useful to have some sort of CPU statistics, even of only measured on Linux Csound, posted in the manual, that would give Csound designers, Cabbage VST and AU plugin and stand-alone developers, Bela and RaspberryPi embedders, WebAudio Csocialites and NFT minters, LiveCoders, and QuiBit Nebulae users (OK… everyone!) some idea of how demanding one or another Csound opcode might be.

(When I Zoom with John ffitch on Tuesday, I will see if he might not want to write something that would measure the CPU load of all opcodes in Csound on a given system and with a given number of cores or …)

Menno, don’t you think this might be nice to have in the manual?
Rory, don’t you think that this might be nice to have in the Cabbage IDE? (as well as a set of displays - in the IDE)
Steven and Hlöðver, don’t you think that this would be nice to have in Web Csound? (a little CPU meter in the menu)
Tarmo, don’t you think this would be nice to have in CsoundQt - a little CPU meter in the menu bar?