Re: SMP on Debian server with Hyperthreading
Just thought I'd add a bit more info... from dmesg:
Linux version 2.4.22 (root@beta) (gcc version 2.95.4 20011002 (Debian
)) #8 SMP Thu Aug 28 14:44:13 HKT 2003
BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000e6000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 000000003f730000 (usable)
BIOS-e820: 000000003f730000 - 000000003f740000 (ACPI data)
BIOS-e820: 000000003f740000 - 000000003f7f0000 (ACPI NVS)
BIOS-e820: 000000003f7f0000 - 000000003f800000 (reserved)
BIOS-e820: 00000000fecf0000 - 00000000fecf1000 (reserved)
BIOS-e820: 00000000fed20000 - 00000000feda0000 (reserved)
119MB HIGHMEM available.
896MB LOWMEM available.
found SMP MP-table at 000ff780
hm, page 000ff000 reserved twice.
hm, page 00100000 reserved twice.
hm, page 000fc000 reserved twice.
hm, page 000fd000 reserved twice.
On node 0 totalpages: 259888
zone(0): 4096 pages.
zone(1): 225280 pages.
zone(2): 30512 pages.
Intel MultiProcessor Specification v1.4
Virtual Wire compatibility mode.
OEM ID: Product ID: Springdale-G APIC at: 0xFEE00000
Processor #0 Pentium 4(tm) XEON(tm) APIC version 20
I/O APIC #2 Version 32 at 0xFEC00000.
Enabling APIC mode: Flat. Using 1 I/O APICs
Kernel command line: auto BOOT_IMAGE=Linux ro root=801
Seems it KNOWS it is SMP... but then it detects only 1 processor? Is this
how hyperthreading works?
----- Original Message -----
From: "Jason Lim" <email@example.com>
Sent: Saturday, 06 September, 2003 1:06 AM
Subject: SMP on Debian server with Hyperthreading
> Hi all,
> Just wondering... I've got a 2.4Ghz Hyperthreading (100% it is the
> hyperthreading model), and the BIOS sees it.
> I then compiled the kernel... the usual, except added the SMP support
> setting "Symmetric multi-processing support". Nothing else was changed.
> Compiled it, liloed it... it's running it:
> # uname -a
> Linux megalith 2.4.22 #8 SMP Thu Aug 28 14:44:13 HKT 2003 i686 unknown
> # mpstat -P
> Not an SMP machine...
> And in top i don't see the multiple CPU usage....
> this is all strange. For Linux, aren't Hyperthreading CPUs suppose to
> like completely separate independent CPUs (this was suppose to change in
> 2.6... but for 2.4, they can't tell the difference, right?).
> Hope you can advise... as hyperthreading is there but not being used,
> which is a waste and could add performance.
> Thanks in advance!
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