Here was my problem:
Bugs Brouillard wrote:
>
> Salutations,
> The "offline" man page states:
> Do not use the psradm command to disable CPUs when benchmarking perfor-
> mance, because the command does not provide an accurate reflection of the
> performance of a system that actually has fewer CPUs. Accurate performance
> results are obtained only when you disable the CPUs at the SRM console com-
> mand level.
>
> How do you disables a cpu at the console? I just looked through the Alpha
> conlose users guide and searched the arckives and could not find out how.
>
> Thanks.
>
Here are the responses. THANK YOU VERRRRY MUCH!!!!
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#From: Matt Lucius QMGPE <mlucius_at_hunch.zk3.dec.com>
Hi...
At the SRM console, there is a variable called cpu_enabled, which holds a
bitmask telling the system which CPUs to turn on. If you're want to boot
the first N cpus, the way I found to remember the right value is "set
cpu_enabled (2^N)-1", so for the first three CPUs, use "set cpu_enabled
7".
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#From: "Hill, NM (Nick) " <N.M.Hill_at_rl.ac.uk>
The console variable to use is cpu_enable. It is a bit map but expressed as
a Hex value! For Example:
00000001 = 1 gives 1 CPU
00000011 = 3 gives 2 CPUs
00000111 = 7 gives 3 CPUs
00001111 = F gives 4 CPUs
etc
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#From: "Colin Walters" <walters_at_zk3.dec.com>
Bugs,
It might depend on what system you are using.
For example, it is " >>> stop <cpu_number>" on a GS60.
If you let me know your model number, I can check its
console commands.
(Hi Collin, our systems are Alpha 2100's)
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#From: alan_at_nabeth.cxo.dec.com
This is almost certainly a system specific detail. It
should be documented in the documentation that came with
the hardware. From a copy of the "AlphaServer 4000 System
Drawer User's Guide" (EK-4000A-UG-A01) that I have, it
appears that you set the console environment variable
"cpu_enable" to a hex value with the zero bit being the
CPUs you want disabled. You can't disable the primary
CPU. While many other systems probably operate the same
way, they could be different.
(Hi Alan, our systems are Alpha 2100's)
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#From: "Rao, Ram" <Ram.Rao_at_compaq.com>
There is a console variable cpu_enabled which allows you to set the CPUs
you would like to use. It is a mask with the LSB being CPU 0 and so on.
For example,
to enable set cpu_enabled to
CPU 0 0x1
CPUs 0,1 0x3
CPUs 0,1,2,3 0xf
Regards,
Ram
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#From: Robert Honore <robert_at_digi-data.com>
Dear Bugs,
To disable one or more cpus at the console level, you change the setting of the
"cpu_enabled" console environment variable. The variable is essentially a bit
vector with one bit for each cpu. The default value is to have all cpus enabled
(that is, all the bits of the bit vector are set to "1"). To disable a cpu, you
need to set the corresponding bit to zero and then execute the "init" command or
power cycle the system.
A bit of explanation about the "cpu_enabled" variable:
For a system that can be configured with up to 4 cpus, the corresponding bit
vector of that system's "cpu_enabled" variable has 4 bits:
1 1 1 1
cpu 3 2 1 0
and they are all set to 1s therefore the corresponding value of the
"cpu_enabled" variable is F (hexadecimal).
If you wanted to disable CPU 2 for instance, you would change the bit vector
thus:
1 0 1 1
cpu 3 2 1 0
by setting the "cpu_enabled" console variable to A (hexadecimal). This you do
by entering the command "set cpu_enabled A" at the console (">>>") prompt.
Hope this helps.
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#From: Oisin McGuinness <oisin_at_sbcm.com>
My copy of the AlphaServer 2000/2100/2100a Firmware reference guide
(nothing similar shipped with later boxes or firmware), EK-AXPFW-RM.C01,
page 1-43, documents the
set cpu_enabled
command thus:
set cpu_enabled hex-digit
"sets a mask that enables or disables specific CPUs on a multiprocessor
system. Disabled CPUs are prevented from running the console
or operating system.... Bit 0 of mask corresponds to cpu 0, bit 1 to cpu 1 etc.
A zero bit prevents corresponding CPU from running, 1 allows...
By default, bit mask is all 1's (hex F), so cpu 0, 1, 2, 3 are all enabled."
(OMcG: What happens on a machine that supports more than 4 cpus???)
There is a handy table on the next page.
I guess
set cpu_enabled 0
would be rather stupid; but
for a 2 cpu box
set cpu_enabled 1
set cpu_enabled 2
would turn off (respectively) cpu 1, cpu 0.
Hope this helps...
...Later Oisin wrote:
Addendum:
I just noticed the note which
says re "set cpu_enabled 0"
"Disables all cpus but CPU 0 still comes up",
so it is hard to be completely stupid, I guess.
----------------------------------------------------------------
Bugs Brouillard Unix system administrator
Humboldt State Univ. Information Technology Services
Arcata, Calif.
707-826-6123
email bb1_at_humboldt.edu
Received on Thu Oct 12 2000 - 20:28:06 NZDT