2.4.9 VM/VMA subsystem works much better

2.4.9 VM/VMA subsystem works much better

Post by Brad Chapma » Fri, 24 Aug 2001 05:00:15



Everyone,

        Just a note: the VMA sanity patch which went in to 2.4.9
has improved Mozilla's performance considerably. I did a rough
calculation based on startup time and found that Mozilla started
approximately 10%-12% faster on 2.4.9 then 2.4.8. Plus, I've
found that swapping is actually starting to work again, although
it still tends to stick at certain times.

        Great job everyone.

Brad

=====
Brad Chapman




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2.4.9 VM/VMA subsystem works much better

Post by Daniel Phillip » Sat, 25 Aug 2001 03:20:09





> > > Everyone,

> > >  Just a note: the VMA sanity patch which went in to 2.4.9
> > > has improved Mozilla's performance considerably. I did a rough
> > > calculation based on startup time and found that Mozilla started
> > > approximately 10%-12% faster on 2.4.9 then 2.4.8. Plus, I've
> > > found that swapping is actually starting to work again, although
> > > it still tends to stick at certain times.

> > >  Great job everyone.

> > Make sure you have my SetPageReferenced patch in, swap is borked without
> > it.

> Can you send me the patches you think should cure a straight 2.4.9 for
> re-testing (probably the one from Marcelo Tosatti, too).
> I am from the old school: don't believe what you can't test. :-)

I took the liberty of cc'ing this to the list.  This patch fixes a severe
swap thrashing problem that was introduced by the use-once patch in 2.4.8.  I
explained the details elsewhere.  Other than the swap problem (which was just
an oversight, not a design error) the use-once strategy seems to be working
fine.  My own anecdotal evidence: before, dpkg --config -a on this box was
effectively a DoS, now I barely notice it while I'm running other
applications.

There should be a similar hole in pagemap_nopage affecting memmapped files,
but nobody has reported it yet.  I presume this is because it's a lot harder
to trigger.  I'll supply a patch after I've looked at it a little more.

--- ../2.4.9.clean/mm/memory.c  Mon Aug 13 19:16:41 2001

                         */
                        return pte_same(*page_table, orig_pte) ? -1 : 1;
                }
+               SetPageReferenced(page);
        }

        /*

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