On Thu, 2020-06-04 at 16:30 -0400, Ben Cotton wrote: > ... The memory used is not preallocated. It's > dynamically allocated and deallocated, on demand. ... > > The system will use RAM normally up until it's full, and then start > paging out to swap-on-zram, same as a conventional swap-on-drive.... Hi, I confess I've absolutely no idea about this, I mean how that works in practice, but when you tell me "we do not allocate on start, we allocate on demand, when the memory is full", then, I hope a logic question is, where do you allocate, when the memory is already full? If there's some threshold, then it's quite the same as preallocate the memory. Let aside how the compression itself works. Does it mean, that the actual outcome will be quicker response (than when using swap on disk) for a price of higher requirements on the CPU (thus it can compress/decompress in a timely manner), thus eventually higher power consumption, thus shorter up time, before the battery is down? I know I can easily misunderstand things, but it feels like a side effect of the compression. Virtual machines. I usually do not give it access to the all host system resources, I give it like 1 or 2 CPUs (sometimes more, but only when I know I want to do something expensive there), and like 2GB of memory (I used to give it one, but since Fedora begun to require at least 2, I increased it). With this swap to RAM on, should I give it even more memory (and eventually CPU), thus Fedora can boot and work reasonably well? When you've a machine with 4GB RAM and 1TB HDD and 1.6GHz CPU, it's much cheaper to use swap on disk than to waste RAM, which should be used for other things (it's even not fully usable 4GB, because some of that can use integrated graphics card). I guess this will penalize such low cost machines, though it needs testing to know for sure. There are devices with a lot less resources (there had been mentioned IoT, under which, I suppose, belong also toys like Raspberry PI, which do not have a lot of RAM (not counting Raspberry PI 4B)), where it might (or might not) hurt even more. My main machine has 16GB RAM. When I run compilation of some bigger projects (like WebKitGTK in my case, but I do not want to even think of giants like LibreOffice), then I face memory pressures, also depending on the target type (debug/release) and how many cores I give to it. It happens from time to time that the whole system freezes (keyboard/mouse doesn't react, neither Caps Lock/Num Lock), with high CPU usage. I suppose it tries to compile, but I never left it run that long, I just turn off the machine and start again, where the new run eventually survives. Should this swap to RAM help anyhow in such situation? > [https://pagure.io/fedora-qa/issue/632 QA: SwapOnzram Test Day] to > discover edge cases, and tweak the default configuration if necessary > to establish a good one-size-fits all approach. The developer usage and average (office) user usage are very different. I'm afraid you cannot find any number, which will fit to all. Bye, Milan _______________________________________________ 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
