←back to thread

Bought myself an Ampere Altra system

(marcin.juszkiewicz.com.pl)
204 points pabs3 | 1 comments | 30 Jun 25 04:38 UTC | HN request time: 0.312s | source
Show context
amelius ◴[30 Jun 25 09:25 UTC] No.44421186[source]▶
> And the latest one, an Apple MacBook Pro, is nice and fast but has some limits — does not support 64k page size. Which I need for my work.

I wonder where this requirement comes from ...

replies(3): >>44421250 #>>44421494 #>>44421603 #
ot ◴[30 Jun 25 09:34 UTC] No.44421250[source]▶
I would guess to develop and test software that will ultimately run on a system with 64k page size.
replies(1): >>44421261 #
amelius ◴[30 Jun 25 09:37 UTC] No.44421261[source]▶
Is there a fundamental advantage over other page sizes, other than the convenience of 64k == 2^16?
replies(4): >>44421331 #>>44421363 #>>44421743 #>>44435389 #
raverbashing ◴[30 Jun 25 09:55 UTC] No.44421363[source]▶
Yes there are

(as a starting point 4k is a "page size for ants" in 2025 - 4MB might be too much however)

But the bigger the page the less TLB entries you need, and less entries in your OS data structures managing memory, etc

replies(1): >>44422104 #
fc417fc802 ◴[30 Jun 25 11:46 UTC] No.44422104[source]▶
4K seems appropriate for embedded applications. Meanwhile 4M seems like it would be plenty small for my desktop. Nearly every process is currently using more than that. Even the lightest is still coming in at a bit over 1M
replies(1): >>44425462 #
p_ing ◴[30 Jun 25 16:55 UTC] No.44425462[source]▶
1M is a huge waste of memory.

Imagine writing out a one sentence note in notepad and the resulting file being 1M on disk.

replies(1): >>44428367 #
1. fc417fc802 ◴[30 Jun 25 22:00 UTC] No.44428367[source]▶
Yet when I reference the running processes on my desktop something like 90% of them have more than 16M resident. So it doesn't appear that even an 8M page size would waste much on a modern desktop during typical usage.

If I'm mistaken about some low level detail I'd be interested to learn more.