Author Topic: Swap read/write speed: are they where they're supposed to be?  (Read 128 times)

Offline gamempire

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Hi PI Community!

I'm trying to optimize my computer and PI settings to try and speed things up a bit, and was looking for some guidance. I've searched the forums here and elsewhere, and there wasn't much information on what the swap write speed should be, just the swap read speeds. I know benchmarks aren't a real world scenario, but I've got 4 benchmark runs to share (two with ram disks, two without).

Computer is a 15" Macbook Pro 2018, Core i9 @ 2.9 GHz with 6 cores, 32GB DDR4 ram. 2TB Apple SSD (my 2010 Macbook Air would have never been able to run PixInsight). Blackmagic SSD benchmark is about 2500mbps write speed, 2700 read speed, which is about where this machine should be from a benchmarking perspective. I know I won't get the best CPU performance on a laptop processor, but it beats my 2nd generation i7 quad core desktop machine from years ago in terms of raw horsepower. Nonetheless, I'm more than impressed with how the CPU performs in this machine.

Swap setup is eight swap directories in /tmp on the SSD, and two ram disks of 4GB each, which seems to be the consensus after reading a number of forum posts breaking down the best practices for swap. Attached are the four PI benchmarks, two with the ram disks, and two without. The transfer speed only drops by about 70-100 mb/s when I remove the ram disks, but I max out around ~1100 mb/s.

Looking at the console log from the benchmarks (with the ramdisks), the write speeds are all over the place, as low as 290 mb/s, and as high as 1100 mb/s. Read speeds are between ~4900 and ~7000 mb/s.

My read speeds are pretty great, but I'm wondering if anyone can comment or advise me if my write speeds are within reason given the machine's specifications.

Thanks much!