Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 19 Oct 2020 16:20:14 +0200 | Subject | Re: [PATCH] lib/test_free_pages: Add basic progress indicators |
| |
Hi Matthew,
On Mon, Oct 19, 2020 at 4:05 PM Matthew Wilcox <willy@infradead.org> wrote: > On Sun, Oct 18, 2020 at 08:12:52PM +0300, Mike Rapoport wrote: > > On Sun, Oct 18, 2020 at 04:01:46PM +0100, Matthew Wilcox wrote: > > > On Sun, Oct 18, 2020 at 04:39:27PM +0200, Geert Uytterhoeven wrote: > > > > On Sun, Oct 18, 2020 at 4:25 PM Matthew Wilcox <willy@infradead.org> wrote: > > > > > On Sun, Oct 18, 2020 at 04:04:45PM +0200, Geert Uytterhoeven wrote: > > > > > > The test module to check that free_pages() does not leak memory does not > > > > > > provide any feedback whatsoever its state or progress, but may take some > > > > > > time on slow machines. Add the printing of messages upon starting each > > > > > > phase of the test, and upon completion. > > > > > > > > > > It's not supposed to take a long time. Can you crank down that 1000 * > > > > > > > > It took 1m11s on ARAnyM, running on an i7-8700K. > > > > Real hardware may even take longer. > > > > > > 71 seconds is clearly too long. 0.7 seconds would be fine, so 10 * 1000 > > > would be appropriate, but then that's only 320MB which might not be > > > enough to notice on a modern machine. > > > > > > > > 1000 to something more appropriate? > > > > > > > > What would be a suitable value? You do want to see it "leak gigabytes > > > > of memory and probably OOM your system" if something's wrong, > > > > so decreasing the value a lot may not be a good idea? > > > > > > > > Regardless, if it OOMs, I think you do want to see this happens > > > > while running this test. > > > > > > How about scaling with the amount of memory on the machine? > > > > > > This might cause problems on machines with terabytes of memory. > > > Maybe we should cap it at a terabyte? > > > > On ARAnyM wih 782 MBytes of RAM running on i7-8650U it takes ~1.75 > > seconds. > > That seems like a somewhat unusual configuration. I think it's pretty > strange to find an actual m68k with more than 128MB of memory. I mean, > I can set up my laptop to believe it has 64TB of memory, and this will > run slowly, but I don't think it's any real problem.
Have you tried it on one of your parisc boxes? They tend to have quite some RAM, compared to CPU speed.
I gave the unmodified test a try on a 1.5 GHz Cortex-A15, which is still a decent arm32 system, and it took 4.25s.
> > Still, I think adding some verbosity to the test wouldn't hurt ;-) > > I prefer the unix philosophy of only emitting messages if something's > wrong.
This is not a normal program, but a test. Alternatively, convert it to kunit, so we'll at least be aware when it starts running, and when it has completed ;-)
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
| |