On Thu, Sep 20, 2018 at 11:49 AM, mcatanzaro@gnome.org wrote:
On Thu, Sep 20, 2018 at 11:34 AM, mcatanzaro@gnome.org wrote:
I'll try it when I can.
Didn't seem to make much difference to me, when building WebKit without -j2 (I normally use -j2 to ensure it doesn't freeze my Fedora). The desktop becomes super sluggish as soon as it starts using swap. then froze after a couple of minutes when it was at around 5 GiB of swap. If it makes things better, great, but it's no solution.
I also wonder about the I/O scheduler. Ubuntu is using the deadline scheduler because it reportedly is better for interactivity, and that is what we want to optimize Workstation for. Perhaps it handles these situations better. Dunno.
deadline favors reads over writes; I'm also not certain it's involved in the swap code path.
5GiB is a lot of swap. I don't see how disabling swap is going to make this better if the system is under that much memory pressure by the application, unless ... the application is giving the kernel unreasonable page eviction hinting to the kernel? zram could plausibly get you 1.5x to 2x RAM since it's compressing with LZ4. If nothing else that'd be an interesting zram stress test.
I've got only 8G on a laptop that I routinely use with -j4 to compile the kernel and it never uses swap.
At this point, the subject is better asked on devel@ as a separate thread and solicit some advice on what's going on (or how to find out what's going on), and whether there's a work around. If you totally disable swap, is this behavior any better?