Pixinsight Performance and Swap Files

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Pixinsight Performance and Swap Files

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Post by Juno16 »


Hi PI users,

I know that many AP’ers here use Pixinsight (PI) for image processing. I just want to pass on what I learned recently about PI performance that you may or may not know.

PI users know that PI consumes quite a bit of system resources. High end cpu’s, ram memory, big video cards, and fast storage disks all contribute to the performance of PI.

The performance of PI is so important to some folks, that many folks spend many thousands of dollars on a stacked high-performance pc (laptop or desktop) to run PI.
Understandably so. Some PI processes and scripts take many minutes to hours to run.

My son and I built my desktop about 2 ½ years ago on a budget.
I kept the budget at $700, but I really just needed the “box” as I had a monitor, keyboard, and 500GB ssd (sata).
I have added a few things the past few years, a ton of storage (10.5TB total) including a nice 2TB nvme m.2 (gen3) boot drive. Using the same 4 ½ year old cpu.

Recently (Christmas) I received a really nice Christmas gift (that I asked for) of 64GB of DDR4 3200 ram. It was an upgrade from the 32GB of DDR4 2667 ram that I had before. Faster and double the capacity.

Many of you PI users are familiar with the benchmark in PI to check performance. It is a script called Pixinsight Benchmark nested under Benchmarks.

I don’t have a benchmark before the ram upgrade, I believe that it was a modest boost (+6-8%), but I have learned a little bit about the PI swap files. It seems that even though PI thrives on huge fast ram memory, it also depends heavily on swap files which seems odd if large amounts of free ram memory are available.
Swap files are temporary files/folders that PI uses (exclusive of ram) to process and temporarily store data. The default PI swap file is created on the local “C” drive.

I read several posts on CN post about increasing the number of swap files. Seems strange, but if you do an internet search, you will find many references to using multiple swap files to increase PI performance.
It helps to have a fast storage drive (nvme or ssd) to create the swap files on, but it also seems that PI performance can be enhanced by creating multiple swap files on even conventional spinning drives.

Below are some tests that I did recently and the results did surprise me.
Yes, spending lots of money on better, faster hardware components can surely increase the performance of PI, but for free, you can create extra swap files that can increase performance to. Sometimes significantly.

Under the EDIT drop down menu, you will find GLOBAL PREFERENCES. At PREFERENCES, select Directories and Network. From there, you can see the default Swap storage directories.

PI Swap File directories default.PNG

This was my PI benchmark score using the single default swap file directory (12456).

Pixinsight Benchmark default swap file.PNG

I created six folders on my C: drive (nvme) to use as temporary swap files (I really don't think that it matter where you create the folders.
Here is the benchmark with no change except using six swap storage directories (15635). A 26% increase in the PI benchmark over the single default swap file directory.

Pixinsight Benchmark 6 swap files on nvme.PNG

I created a 16GB ramdrive (out of my 64GB of total ram) using free software and dedicated it to swap file directories.

Pixinsight Benchmark 6 swap files on ramdrive.PNG

The benchmark went up to 16236 a 30% increase in the PI benchmark from using the single default swap file directory. A very significant increase for free!

I have since tested both the nvme and ramdrive with four swap file directories and the performance was basically the same as with six swap file directories. So, some fine tuning can help.

Your mileage may vary depending on your hardware.

Hope that this is helpful!
Jim

Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), Orion 50mm Guide Scope, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, Orion SSAG, IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
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Juno16 United States of America
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Articles: 0
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Posts: 8195
Joined: Sun May 12, 2019 3:13 pm
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Location: Mississippi Gulf Coast
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Re: Pixinsight Performance and Swap Files

#2

Post by Juno16 »


Also to note.

I thought that since all of the multiple swap files were on the same drive, I would mix up a combination of several swap files on the ram drive and several on the nvme drive.
Unfortunately, there was no performance gain by doing that.

Still, a 30% improvement by simply creating multiple swap files on a ran drive vs. the PI default single swap file for no cost is a bargain in my book.
Jim

Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), Orion 50mm Guide Scope, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, Orion SSAG, IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
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