FreeBSD replaces bubblesort with mergesort on SYSINTs, results in 100x speed

Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by srcreigh on Monday August 21, 2023 @01:37AM (#37205806)

Very OT, but I concur. I need a DSP for my car audio system. I considered a rpi3 with a DAC attachment.

I tried the raspbian OS with some moderate overclocking and removing unneeded startup processes. Couldn’t get it under 25 seconds for boot.

Maybe I’ll try again with an RPi 4 and usb3 nvme. or maybe I’ll just pay hundreds of dollars for a dedicated DSP unit.

In case anyone cares, my main use case is parametric EQ for phon adjusted low bass frequencies. 90dB 20Hz sounds as loud as 70dB 50Hz (give or take) and subwoofers are generally quieter at lower frequencies anyways. Hence, audio processing unit to cut as you go higher than your lowest decently loud frequency.

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by ju-st on Monday August 21, 2023 @01:49AM (#37205862)

You could use a ADAU1701 DSP board (cheaper and shittier minidsp) or do it directly on a modern/fast microcontroller, e.g. ESP32. I used an ESP32 to adjust frequency response of a small diy loudspeaker (and added Bluetooth).

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by JeffeFawkes on Monday August 21, 2023 @02:20AM (#37206028)

If you make your own buildroot image, you can get VERY quick boot times - here's a random vid I found [1] with 3.5 seconds on a pi zero w (which is considerably less powerful than a Pi3.

I've worked with similarly underpowered boards (licheepi zero, only has 64mb ram and uses the cpu from a dashcam!) and those will still boot and start an SDL app in under five seconds.

If you can identify the bare minimum that you need for your EQ solution, you can probably get similar boot times.

[1]: https://www.youtube.com/watch?v=ZehLyumyMvE

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by kragen on Monday August 21, 2023 @06:20AM (#37207496)

i feel like maybe 3.5 seconds is not VERY quick compared to 28 milliseconds?

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by cinntaile on Monday August 21, 2023 @06:23AM (#37207511)

The use case is different so the comparison doesn't really matter.

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by kragen on Monday August 21, 2023 @06:34AM (#37207586)

3.5 seconds might be tolerable for your car radio i guess

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by srcreigh on Monday August 21, 2023 @09:24PM (#37217460)

Yep. My head unit has its own startup time for digital audio inputs, around 2-3s.

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by yjftsjthsd-h on Monday August 21, 2023 @11:04AM (#37210527)

28ms is a VM; in hardware you can't get through firmware in 28ms. Apples to oranges.

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by kragen on Monday August 21, 2023 @08:35PM (#37217114)

true if your firmware is shitty enough but plenty of hardware platforms don't have that problem

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by red0point on Monday August 21, 2023 @02:38AM (#37206115)

It doesn‘t always have to be a RPi, sometimes there is dedicated hardware for that use case that is also kinda cheap.

Check this thing out, it‘s a programmable audio DSP:

https://www.thomannmusic.ch/the_t.racks_dsp_4x4_mini.htm

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by SomeoneFromCA on Monday August 21, 2023 @04:21AM (#37206744)

Can't you just run on bare metal on rpi? Also a resistor, a capacitor and a realay would work to filter out the extra bass.

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Re:FreeBSD replaces bubblesort with mergesort on SYSINTs, re... by pid-1 on Monday August 21, 2023 @08:21AM (#37208477)

Search ebay etc... for Texas Instruments DSP evaluation boards.

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