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guenthert 11 hours ago

So much polemic and no numbers? If it is a performance issue, show me the numbers!

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cdown 11 hours ago | parent [-]

There are quite a few numbers in the article, although of course I'm happy to hear any more you'd like presented.

* A counterintuitive 25% reduction in disk writes at Instagram after enabling zswap

* Eventual ~5:1 compression ratio on Django workloads with zswap + zstd

* 20-30 minute OOM stalls at Cloudflare with the OOM killer never once firing under zram

The LRU inversion argument is just plain from the code presented and a logical consequence of how swap priority and zram's block device architecture interact, I'm not sure numbers would add much there.

	▲	guenthert 10 hours ago \| parent [-]
		> The LRU inversion argument is just plain from the code presented and a logical consequence of how swap priority and zram's block device architecture interact, I'm not sure numbers would add much there. Yes, while it is all very plausible, the run times of a given workload (on a given, documented system) known to cause memory pressure to the point of swapping with vanilla Linux (default swappiness or some appropriate value), zram and zswap would be appreciated. https://linuxblog.io/zswap-better-than-zram/ at least qualifies that zswap performs better when using a fast NVMe device as swap device and zram remains superior for devices with slow or no swap device.