cdown

11 ms·

1.
by cdown 6mo ago
This is actually something we're actively working on! Nhat Pham is working on a patch series called "virtual swap space" ( https://lwn.net/Articles/1059201/ ) which decouples zswap from its backing st
2.
by cdown 6mo ago
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 rati
3.
by cdown 6mo ago
Thank you for reading and your critique! What you're describing is definitely a real problem, but I'd challenge slightly and suggest the outcome is usually the inverse of what you might expect. One of the counterintuitive things h
4.
by cdown 5y ago
Hey there! Article author here -- just found out this was posted here and going through the comments :-) One of the earliest test versions of my patch actually did inode reuse using slabs just like you're suggesting, but there are a fe
5.
by cdown 6y ago
My e-mail address is already public from my kernel commits and upstream work. :-)
6.
by cdown 6y ago
Hey! Facebook engineer here. If you have it, can you send me the User-Agent for these requests? That would definitely help speed up narrowing down what's happening here. If you can provide me the hostname being requested in the Host he
7.
Show HN: Alert when oversaturated using PSI, *before* machine slows to a crawl(github.com)
1 points by cdown 6y ago|0 comments
8.
by cdown 7y ago
I had no idea anyone would find this so fast, so I thought it would be safe to change the url to match the final title before posting anywhere -- how wrong I was. It's back now. Thanks!
9.
The curious case of stalled squashfs reads(chrisdown.name)
2 points by cdown 8y ago|0 comments
10.
by cdown 9y ago
There are some systems which are memory-bound by nature, not as a consequence of poor optimisation, so it's not really as simple as "needed" or "not needed". As a basic example, in compression, more memory available
11.
by cdown 9y ago
I mean, it really depends on your application how non-trivial the performance improvement will be, but this statement isn't theoretical -- memory bound systems are a major case where being able to transfer out cold pages to swap can be
12.
by cdown 9y ago
> how much time did I spend waiting to swap-in a page You can do this with eBPF/BCC by using funclatency ( https://github.com/iovisor/bcc/blob/master/tools/funclatency... ) to trace swap relat
13.
by cdown 9y ago
> Once desktop systems and applications support required APIs to handle saving state before being shut down. SIGTERM and friends? :-) If your application is just dropping state on the floor as a result of having an intentionally trappabl
14.
by cdown 9y ago
> I never saw programs I would actually want to use try to allocate that much What about applications that have memory-bound performance characteristics? In these cases, saving a bit of memory often directly translates into throughput, w
15.
by cdown 9y ago
One problem with relying on the OOM killer in general is that the OOM killer is only invoked in moments of extreme starvation of memory. We really have no ability currently in Linux (or basically any operating system using overcommit) to de
16.
by cdown 9y ago
> In my experience, a misbehaving linux system that's out of RAM and has swap to spare will be unusably slow. Yeah, this is basically the main drawback of swap. I tried to address this somewhat in the article and the conclusion: &gt
17.
In defence of swap: common misconceptions(chrisdown.name)
2 points by cdown 9y ago|1 comments
18.
Cgroupv2: Linux's new unified control group hierarchy(youtube.com)
3 points by cdown 10y ago|0 comments
19.
by cdown 10y ago
Here's the technical whitepaper: https://fbnewsroomus.files.wordpress.com/2016/07/secret_conv...
20.
FOSDEM 2016: Lessons learned running SSL at scale at Facebook(youtube.com)
3 points by cdown 11y ago|0 comments
21.
by cdown 11y ago
If you really want to store a "lifetime of photos", you should probably consider having a better long-term backup strategy than just putting it in locations that are managed by a single piece of software. :-) Sure, some of these a