Re: [Csnd-dev] [EXTERNAL] Re: [Csnd-dev] Parallel Csound performance

yes, it is running correctly. Output waveforms are the same.
========================
Prof. Victor Lazzarini
Maynooth University
Ireland

> On 29 Oct 2025, at 23:12, Steven Yi <[email protected]> wrote:
> 
> I'd be careful about it running fast but incorrectly. That's always
> been my concern with ParCS is correctness.
> 
> On Wed, Oct 29, 2025 at 6:22 PM Victor Lazzarini
> <[email protected]> wrote:
>> 
>> No, I don't think we ever disabled it. There were some questions about re-enabling some analysis to the parser (which existed in parser 2) but beyond that we never touched it.
>> 
>> I continued to build with it but had not been actively testing the code. I am surprised at how well it run without any changes.
>> 
>> best
>> Prof. Victor Lazzarini
>> Maynooth University
>> Ireland
>> 
>>> On 29 Oct 2025, at 22:14, Steven Yi <[email protected]> wrote:
>>> 
>>> *Warning*
>>> 
>>> This email originated from outside of Maynooth University's Mail System. Do not reply, click links or open attachments unless you recognise the sender and know the content is safe.
>>> 
>>> This is odd, as I thought cspar was disabled in Csound?
>>> 
>>>> On Wed, Oct 29, 2025 at 6:08 PM Victor Lazzarini
>>>> <[email protected]> wrote:
>>>> 
>>>> I’m back investigating parallel Csound performance and it was interesting to see that
>>>> Csound 7 is working well with it, in fact far better than 6.18.
>>>> 
>>>> Running 1000 oscillator instrs for 60 secs I got these stats
>>>> 
>>>> ksmps = 100
>>>> -----------
>>>> single thread: 3.9s
>>>> 8 threads: 3.9s
>>>> 
>>>> ksmps = 150
>>>> ----------
>>>> single thread: 3.5s
>>>> 8 threads: 2.7s
>>>> 
>>>> ksmps = 300
>>>> ----------
>>>> single thread: 3.2s
>>>> 8 threads: 1.6s
>>>> 
>>>> ksmps = 500
>>>> ----------
>>>> single thread: 3.2s
>>>> 8 threads: 1.2s
>>>> 
>>>> ksmps = 1000
>>>> ----------
>>>> single thread: 3.3s
>>>> 8 threads: 0.8
>>>> 
>>>> In comparison with 6.18 the last test ran at 11secs for 8 threads. In fact, 6.18 was always slower in parallel
>>>> performance. Something was very broken there. Single-threaded performance is on a par with Csound 7.
>>>> 
>>>> I can only think the new parser is working better with the parallel dispatch, or that something else was wrong
>>>> in the 6.x and got fixed in 7. Anyway, I am pleased with these results. In general, ksmps=100 seems to be the break even
>>>> point, below that multi-threaded performance is always losing. Also ksmps=1000 is more or less the highest gain,
>>>> with diminishing returns after that. In my computer, 8 threads seem to be the optimal.
>>>> 
>>>> best
>>>> ========================
>>>> Prof. Victor Lazzarini
>>>> Maynooth University
>>>> Ireland
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>>