On 5/31/26 19:36, void wrote: > On Sun, May 31, 2026 at 06:28:17PM -0700, Mark Millard wrote: >> On 5/31/26 03:08, void wrote: >> >> How much swap do you use with that 320 GiBytes of RAM? >> >>> >>> Here's top output during the electron41 build >>> >>> last pid: 76928; load averages: 22.02, 21.41, 21.32 up >>> 8+23:06:29 20:17:14 >>> 184 threads: 20 running, 164 sleeping >>> CPU: 89.4% user, 0.0% nice, 10.6% system, 0.0% interrupt, 0.0% idle >>> Mem: 84G Active, 74G Inact, 29G Wired, 1176M Buf, 188G Free >>> ARC: 16G Total, 8693M MFU, 4833M MRU, 1368K Anon, 192M Header, 2607M >>> Other >>> 12G Compressed, 19G Uncompressed, 1.61:1 Ratio >>> Swap: 4096M Total, 4096M Free > > 4096M swap
So RAM+SWAP = 324 GiBytes instead of 320 GiBytes: RAM+SWAP = 1.0125*RAM. Seems unlikely to make much of a difference in the failure rate associated with running out of swap space, such as via tmpfs competition for RAM+SWAP. For 64-bit contexts, I use more like RAM+SWAP = 4.75*RAM when I have the overall storage to not force a tradeoff. The one place where a tradeoff was force I have more like RAM+SWAP = 3.66*RAM. I use vm.pageout_oom_seq to generally avoid OOM kills before running out of RAM+SWAP. 4.75 or so (or less) avoids FreeBSD warning of potential mistuning for my RAM contexts from 8 GiByte to 192 GiByte. As I remember, sufficiently smaller RAM sizes needed more like 4.6 or 4.5 to avoid the warning. I've probably not ever used less than 1 GiByte system for such activities. Because of my very rare `bulk -ca` experiments, I blacklist the tmpfs use of what would otherwise be large usage of tmpfs, as well as doing some mutual exclusion. Otherwise I build less of a variety of such than you do. I also avoid spinning rust storage media. -- === Mark Millard marklmi at yahoo.com
