Mark Ovens wrote:
I've never had any success with the ULE scheduler on my dual Athlon
box running RELENG_5; it was so unstable it made Windows 3.1 look
stable. In fact my current build, cvsup'd a couple of days ago, won't
even boot with ULE.
From what I remember, ULE was intended to become the default scheduler
during the life of 5.0 but that hasn't happened.
I've just cvsup'd the source for RELENG_6 and I'm surprised to find in
the GENERIC config file:
#options SCHED_ULE # ULE scheduler
options SCHED_4BSD # 4BSD scheduler
so it seems 4BSD is still the default scheduler. Is ULE _still_
considered to be in development/experimental? Even the SMP config file
doesn't use ULE.
Also in GENERIC:
options PREEMPTION # Enable kernel thread preemption
[....]
options ADAPTIVE_GIANT # Giant mutex is adaptive.
Yet in src/sys/conf/NOTES, ADAPTIVE_GIANT is listed under SMP Options
and PREEMPTION is listed under SMP Debugging Options which makes it
surprising that they are in the GENERIC config file.
What I am trying to decide is whether there any point in making the
jump from a very stable RELENG_5 system to RELENG_6. AIUI the ULE
scheduler and it's associated options optimize the use of multiple
CPUs and by staying with 4BSD I'm not getting the best performance
from my system.
Can anyone offer any advice on this please?
The machine has dual Athlon MP2800s on a Asus A7M266-D mobo, 1Gbyte
ECC RAM and all SCSI disks and optical drives.
I have been benchmarking a Java servlet under ULE, and I couldn't get
result scores as high under ULE as I could under the regular the 4BSD
(although it wasn't far off) and when I left the machine benchmarking
all night under ULE I came back in the morning to find the machine
unresponsive and in need of a hard reboot.
Mike
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