On Wednesday, July 8, 2020 12:53:05 PM MST Przemek Klosowski via devel wrote: > On 7/8/20 12:15 PM, John M. Harris Jr wrote: > > Really, this is starting to sound like it's more of an issue with web > > browsers, and less of a problem with our current configurations, without > > EarlyOOM needlessly killing things. > > [...] > > Currently, pages that haven't been used in a while are the ones that would > > get swapped out first, which I'm sure we can all agree is the most sane > > option. Your GIMP example is accurate, but that'll take a fraction of a > > second. > Argumentative, Your Honor! It's not just an issue with web > browsers---you say that yourself few lines further down, it happens with > every program that uses big data---GIMP with lots of images, FreeCAD > with a complex geometry, rmaxima with a combinatiorally exploding > symbolic expression, even your editor where you read in the entire > /var/log/httpd/access_log against your better judgement. Literally all > those examples happened to me fairly recently---the system went > unresponsive, essentially requiring hard reset, whereas the preferred > outcome would have been to abort those runaway tasks. That other software's data would get swapped out doesn't mean "it's not just an issue with web browsers". It's not an issue with anything else. It's okay to swap out a few pages, and it doesn't hurt GIMP, FreeCAD, etc. If it does with browsers, that's a bug. > >> One way to think about it is that disk is tens of thousands times slower > >> than RAM. If you need to use it, your system is commensurably slower. > >> That's why zram is such a good idea. Swap was always a tradeoff: you > >> saved $'s not spent on RAM, and paid with your time sitting idle waiting > >> for the computer. > > > > Well, no. It's not "tens of thousands times slower than RAM". If you need > > to use it, you're swapping in a few pages at a time, not the entire > > contents of swap. Swap isn't a replacement for RAM. It's an optimization > > that doesn't waste RAM needlessly. > > I think we both understand what the other person is trying to say, to > the point where no further explanations are needed. Having said that, > I'd prefer if you would qualify and augment instead of denying my > statements. I stand by both of them: > > * disk access is literally O(10000) slower than RAM access This is just false, and you can prove that on your own system using only `dd`. In fact, if your system is newer than my Lenovo ThinkPad X200 Tablet, you'll probably have even faster reads/writes from/to disk. > * swap is a cheap substitute for RAM, with the right swap/RAM mix > determined by cost-benefit considerations It can be used as such, but really shouldn't be. It's more of an optimization such that you don't waste RAM than anything else. > You're right that there's a sweet spot where swap just provides a buffer > for occasional peak demand---but this entire discussion results from > complaints about system behavior under heavy swap use, when swap is > being an inadequate replacement for the needed RAM. That's not what this discussion results from. This discussion results from somebody outside the KDE SIG deciding the KDE Spin needs EarlyOOM killing our applications at random, and ruining our desktop experience. -- John M. Harris, Jr. _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
