Fork / exec / ctx overhead (on macppc)

[Havard.Eidnes%runit.sintef.no@localhost]

Hi,

here's part of lmbench results for 4 of my test/build systems,
two of which are "before" and "after" I upgraded my macppc with a
new CPU board.

It appears that the macppc code is comparatively slow at doing
fork and exec, possibly also a little slow in doing context
switching.

Does anyone know what might be the reason for this?  I suppose
this is a CPU-specific performance problem rather than a port-
specific problem?

Regards,

- Håvard

------------------------------

Processor, Processes - times in microseconds - smaller is better
----------------------------------------------------------------
Host               OS  Mhz null null      open selct sig  sig  fork exec sh
                           call  I/O stat clos       inst hndl proc proc proc
------- ------------- ---- ---- ---- ---- ---- ----- ---- ---- ---- ---- ----
604-mac NetBSD 1.4.2A  133  2.8  9.8   75  103 0.18K  6.6   15 41.7K  75K 147K
G3-mac  NetBSD 1.4.2A  350  1.0  3.3   19   23 0.05K  2.2    4 29.3K  53K 103K
alpha   NetBSD 1.4.1   500  0.7  4.7   20   25 0.06K  1.8    6  1.8K   6K  11K
i386    NetBSD 1.4.1   333  1.1  3.9   17   25 0.04K  2.5    4  0.9K   4K   7K

Context switching - times in microseconds - smaller is better
-------------------------------------------------------------
Host                 OS 2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K 16p/64K
                        ctxsw  ctxsw  ctxsw ctxsw  ctxsw   ctxsw   ctxsw
--------- ------------- ----- ------ ------ ------ ------ ------- -------
604-mac   NetBSD 1.4.2A   17    214    823   253   1056     293    1105
G3-mac    NetBSD 1.4.2A          99    777   220    787     216     785
alpha     NetBSD 1.4.1     3     15    112    46    260      62     317
i386      NetBSD 1.4.1     9     34     79    35    184      44     244