Linux

Too bad, this isn't happening as a kernel patch. Adding to that point:

The key detail is that CRAM is a hardware implementation of compression, meaning the logic is in the memory controller rather than in software, so it's not a pure software trick like ZRAM. However, it uses standard off-the-shelf DRAM and a normal memory bus, so no exotic modules or custom interfaces are required.

The person who came up with this acronym is probably proud of their work lol

Could already do that with zram!

I feel like ZRAM showed up when prices were historically low

When I was in computer science in college back in the 1900s, they told us that the USSR was responsible for some of the best algorithms still in use at the time (both for RAM and CPU usage) because they just had less to work with.

Guess we're all in that boat now.

This is still just a bandaid over running 10 copies of chromium for each electron app.

You know it's getting weird out there when Meta seems to be doing something that's actually useful.

Necessity is the mother of invention.

It's a little better than your read. The ~400x speedup is in comparison to using ZRAM, which, in very brief terms, compresses memory by creating an in-memory compressed block device and assigning that as your swap space. So your "swap" is actually a compressed chunk of RAM, not on disk.

This was significantly slower than normal memory access because page faulting when looking up something in memory then fetching from swap was, itself, expensive. Regardless of how fast that swap was. When your swap is on a storage device that overhead is comparatively tiny, but when it's just another chunk of memory suddenly it's what you're spending most of your time on.

I'm not sure if this is misleading at all. If anything, they should have mentioned compared to ZRAM. Title is incomplete, but I don't think it is intentionally misleading here. It just looks like they expect the reader to know CRAM is a replacement for ZRAM. The new compression method CRAM with over 400x speedup is compared to ZRAM method:

A new compression model, called CRAM, offers a different path to compression that avoids swap entirely by keeping the compressed data in memory, and it offers up to 452x the performance of ZRAM.

Because CRAM is stored in RAM and treated as RAM, with full cacheline/byte access, it can be accessed in a read-only fashion with little delay; just the cost of hardware-offloaded compression. As a result, CRAM "runs at DRAM speed," as the creator says in the slide above. While the graph already looks impressive, it's a logarithmic scale; CRAM, in the worst case, is doing 489 million operations per second versus ZRAM's 1.1 million. It's barely comparable.

Even when you enable writes, CRAM is still much faster than ZRAM; 5.4x in the worst tested case of 20% writes. That's a huge drop from the 452x read-only case, but keep your context; a 5.4x speedup is still titanic.

Is writes enabled CRAM / ZRAM common? If so, then the post title is definitely misleading.

I remember an old DOS utility called Ram Doubler. Sadly it also halved the speed.