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Old 19th January 2015
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Default "the OpenBSD kernel will only recognize 3.1 gig of RAM"?

While browsing through some of the great tutorials at calomel, I noticed this blurb:

Quote:
For OpenBSD on our testing system we had eight(8) gig available, but the OpenBSD kernel will only recognize 3.1 gig of that no matter if you use the i386 or AMD64 kernel. In fact, having too much RAM in your box will COST you memory on OpenBSD, as more kernel memory is used up tracking all your RAM. So cutting your ram to 2 GB will probably improve the upper limit. Strange but true.
Is this true?
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Old 19th January 2015
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No. Not since bigmem became the default for OpenBSD/amd64 on April 4, 2011, for inclusion in OpenBSD 5.0.

Prior to that, bigmem had about 3 years of testing by developers and interested users who were building custom kernels to enable it.

Ref: http://cvsweb.openbsd.org/cgi-bin/cv...-cvsweb-markup

Last edited by jggimi; 19th January 2015 at 05:48 PM. Reason: added link
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Old 19th January 2015
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Quote:
Originally Posted by hanzer View Post
Is this true?
Reading through the misc@ archives, that site is notorious for posting incorrect information:

http://marc.info/?l=openbsd-misc&w=2&r=1&s=calomel&q=b
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Old 19th January 2015
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Quote:
Originally Posted by jggimi View Post
Not since bigmem became the default for OpenBSD/amd64 on April 4, 2011, for inclusion in OpenBSD 5.0.
Thanks. For an i386 machine, I guess it doesn't make sense to install more than 4GB of RAM?
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Old 19th January 2015
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For i386, the addressable physical memory limit is 3 GB. The 4th GB, if installed, is not addressable. It is my understanding that PAE is used on OpenBSD with virtual address spaces (per process), not physical addressing.

http://en.wikipedia.org/wiki/3_GB_barrier
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Old 19th January 2015
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Default addito salis grano

Quote:
Originally Posted by ocicat View Post
Reading through the misc@ archives, that site is notorious for posting incorrect information:
In my experience, errors, ambiguities, omissions, distortions, obfuscations, etc. are fairly common everywhere. I find the articles posted on "that site" to be useful overviews and generally pleasant to read, FWIW.
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Old 20th January 2015
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Quote:
Originally Posted by hanzer View Post
While browsing through some of the great tutorials at calomel, I noticed this blurb:



Is this true?
Bullshit

Code:
predrag@oko$ uname -a
OpenBSD oko.bagdala2.net 5.6 GENERIC.MP#2 amd64
predrag@oko$ sysctl hw | grep mem
hw.physmem=8568832000
hw.usermem=8568791040
Check out misc for my posts with dmesg. About year ago I send dmesg from the server with 64 cores and 512 GB of physical RAM (running OpenBSD amd64). Server ended up running Red Hat because we are using it as a computing node. I will try to dig one of my sparc64 machines with lots of RAM and post dmesg.
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Old 20th January 2015
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Quote:
Originally Posted by hanzer View Post
Thanks. For an i386 machine, I guess it doesn't make sense to install more than 4GB of RAM?
PAE is being working on now:
http://marc.info/?l=openbsd-tech&m=142122093110713&w=2
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Old 20th January 2015
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Quote:
Originally Posted by ibara View Post
PAE is being working on now...
I missed that note at the bottom of mlarkin@'s Email. Thanks!
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