Messages in this thread |  | | Date | Sat, 3 Nov 2001 20:07:16 +0100 (CET) | From | Mike Galbraith <> | Subject | Re: 2.4.14-pre6 |
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On Sat, 3 Nov 2001, Linus Torvalds wrote:
> On Sat, 3 Nov 2001, Mike Galbraith wrote: > > > > > Otherwise -pre5aa1 still seems to be the fastest kernel *in this test*. > > > > My box agrees. Notice pre5aa1/ac IO numbers below. I'm getting > > ~good %user/wallclock with pre6/pre7 despite (thrash?) IO numbers. > > Well, pre7 gets the second-best numbers, and the reason I really don't > like pre5aa1 is that since pre4, the virgin kernels have had all mapped > pages in the LRU queue, and can use that knowledge to decide when to > start swapping. > > So in those kernels, the balance between scanning the VM tables and > scanning the regular unmapped caches is something that is strictly > deterministic, which is something I _really_ want to have. > > We've had too much trouble with the "let's hope this works" approach. > Which is why I want the anonymous pages to clearly show up in the > scanning, and not have them be these virtual ghosts that only show up when > you start swapping stuff out. > > Your array cut down to just the ones that made the benchmark in under 8 > minutes makes it easier to read, and clearly pre6+ seems to be a bit _too_ > swap-happy. I'm trying the "dynamic max_mapped" approach now.
Swap-happy doesn't bother this load too much. What it's really sensitive to is pagein. Turning the cache knobs (vigorously:) in aa-latest...
2.4.14-pre6aa1 real 8m29.484s user 6m38.650s sys 0m27.940s
user : 0:06:45.45 70.6% page in : 641298 nice : 0:00:00.00 0.0% page out: 634494 system: 0:00:41.73 7.3% swap in : 118869 idle : 0:02:06.90 22.1% swap out: 154141
echo 2 > /proc/sys/vm/vm_mapped_ratio echo 128 > /proc/sys/vm/vm_balance_ratio
real 7m25.069s user 6m37.390s sys 0m27.540s
user : 0:06:43.60 78.7% page in : 588488 nice : 0:00:00.00 0.0% page out: 514865 system: 0:00:40.47 7.9% swap in : 118738 idle : 0:01:08.92 13.4% swap out: 122340
..lowers the sleep time noticibly despite swapin remaining constant.
-Mike
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