Memory >3.5GB not used?

[Ivan Voras]

Bill Moran wrote:
> In response to "Don O'Neil" <lists at lizardhill.com>:
> 
>> I never had this problem before when I built the kernel the first time.
>> Could my module source be corrupt? If so, how do I re-install just the
>> kernel sources for 6.1?
> 
> Not all modules work with PAE.  Read the example PAE kernel file for
> information.
> 
> PAE is an awful hack, BTW.  I've heard a number of people complain that
> performance sucks under PAE.

It greatly depends on the workload. For example, these are my results
with unixbench:


PAE:
                     INDEX VALUES
TEST                                        BASELINE     RESULT      INDEX

Dhrystone 2 using register variables        116700.0  6404191.9      548.8
Double-Precision Whetstone                      55.0     1444.6      262.7
Execl Throughput                                43.0     2374.5      552.2
File Copy 1024 bufsize 2000 maxblocks         3960.0    47618.0      120.2
File Copy 256 bufsize 500 maxblocks           1655.0    41809.0      252.6
File Copy 4096 bufsize 8000 maxblocks         5800.0    58002.0      100.0
Pipe Throughput                              12440.0  1018477.4      818.7
Pipe-based Context Switching                  4000.0    32811.6       82.0
Process Creation                               126.0     4491.9      356.5
Shell Scripts (8 concurrent)                     6.0      638.0     1063.3
System Call Overhead                         15000.0   798137.5      532.1
                                                                 =========
     FINAL SCORE                                                     317.2



NO PAE:
                     INDEX VALUES
TEST                                        BASELINE     RESULT      INDEX

Dhrystone 2 using register variables        116700.0  6673515.4      571.9
Double-Precision Whetstone                      55.0     1475.1      268.2
Execl Throughput                                43.0     2335.9      543.2
File Copy 1024 bufsize 2000 maxblocks         3960.0    43796.0      110.6
File Copy 256 bufsize 500 maxblocks           1655.0    39474.0      238.5
File Copy 4096 bufsize 8000 maxblocks         5800.0    57819.0       99.7
Pipe Throughput                              12440.0   998089.5      802.3
Pipe-based Context Switching                  4000.0    25928.4       64.8
Process Creation                               126.0     5043.9      400.3
Shell Scripts (8 concurrent)                     6.0      697.0     1161.7
System Call Overhead                         15000.0   792628.3      528.4
                                                                 =========
     FINAL SCORE                                                     312.7

The final score is better in PAE case because IO performance measured
better, but in this case I know this particular benchmark can be
ignored, but the rest of the numbers should be fine.

In short, PAE is worse, but not horribly so.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 250 bytes
Desc: OpenPGP digital signature
Url : http://lists.freebsd.org/pipermail/freebsd-questions/attachments/20070424/81ffbec8/signature.pgp