You are measuring sequential throughput with a block size of 10M. Swap I/O is random 4K pages (with default readahead 32K and clustered swapout 1M), with the read latency being the most important factor.

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fpoling 2 days ago | parent [-]

> are measuring sequential throughput

On SSD I am measuring LUKS performance in fact as IO is much faster then LUKS encryption using specialized CPU instructions. As I wrote, without LUKS the numbers at least twice faster even with random access.

The point is that in 2025 with the latest SSDs there is no point in using compressed memory. Ewen with LUKS encryption it will be faster than even highly tuned swap setup.

In 2022-23 when LUKS was not optimized it was different so I used hardware encryption on SSD after realizing that even lz4 compression was significantly slower than SSD.

	▲	fpoling 2 days ago \| parent [-]
		EDIT: while its true that on purely random 4K SSD performance degrades badly, with 32K random read/writes it is still above 2 GB/s so in practice it is LUKS that is the bottleneck, not SSD.