Subject: Re: Are there any known problems with uvm or pmap in -current as of about Oct. 16?
To: Chuck Silvers <chuq@chuq.com>
From: James Chacon <jchacon@genuity.net>
List: port-macppc
Date: 11/05/2001 08:34:22
Any reason not to make this the default in GENERIC for now?

James

>
>hi,
>
>matt and I spent a bunch of time working on the NEWPMAP problems today,
>and we found and fixed several bugs.  our stress-test was "make -j 20" in
>a kernel build dir.  when we started this morning, it took about 30 seconds
>to trigger one of the assertions.  a few minutes ago a test run completed
>without a problem after 60 minutes.
>
>at this point the new pmap appears to be much more stable than the old one,
>so I recommend that everyone turn on "options NEWPMAP" if you haven't
>done so already.
>
>-Chuck
>
>
>On Tue, Oct 30, 2001 at 08:13:44PM -0800, Monroe Williams wrote:
>> on 10/26/01 7:03 PM, Chuck Silvers at chuq@chuq.com wrote:
>> 
>> > the bug in the new pmap that people have complained about causes a panic
>> > when some sanity-checking code notices that the internal pmap state
>> > has become inconsistent.
>> > 
>> > if you haven't had any problems with the old pmap, don't switch to the new
>> > one.
>> > these pmap bugs are the sort that seem to only affect some people and not
>> > others.  I've never had any problems with either pmap myself, but then
>> > I don't do much with my powermac.
>> 
>> With a -current kernel and the old pmap, the machine I'm working with
>> reliably panics in short order (less than 1/2 hour).  I never saw this panic
>> in testing, but when I deployed the new machine it made for an exciting day
>> until I reverted to the old server.
>> 
>> When you're talking about IS, exciting == bad.
>> 
>> This machine _does_ get used for a lot, and random panics just aren't
>> acceptable.
>> 
>> Is someone actively working on fixing the bugs in the new pmap?  I really
>> hate to hear that -current macppc kernels Just Aren't Reliable with either
>> pmap, but that seems to be what the evidence suggests.
>> 
>> A 1.5.2 kernel just doesn't make good use of the 1.25G of RAM in this box,
>> but that's what I'm planning to deploy this weekend, if I can figure out the
>> proper settings for BUFPAGES & friends.  I may end up downgrading to 512M to
>> get the kernel to boot...
>> 
>> -- monroe
>> ------------------------------------------------------------------------
>> Monroe Williams                                  monroe@criticalpath.com
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