Hyperthreading hurts 5.3?

[Timothy Luoma]

On Jan 11, 2005, at 9:09 PM, David Kelly wrote:

> The benefits of HT are too few for me to risk trashing the fs now its 
> full.

That's a good enough reason for me.

>> Iif YES, I wasn't clear if people meant "disable in BIOS" or just some
>> configuration setting in a *.conf file.
>
> In the BIOS.

Thanks...

>> (disabling HT will apparently mean I have to reinstall XP on the other
>> drive.
>
> What does XP have to do with it?

Sorry to be unclear, XP is on the other drive.  I called Creative Tech 
Support today to inquire why XP might die (BSOD) immediately on driver 
install for the serial port modem I bought from them.  He immediately 
diagnosed this as a machine with HT enabled, and said that the way that 
IRQs are assigned is "different".  (Someone else told me that Creative 
released new drivers but they hadn't helped.)

He said the only way to use the modem would be to a) get a USB version 
[which I assumed wouldn't work well with FreeBSD] or b) disable HT, but 
because XP installs itself "differently" if it senses a 
"multiprocessor" I would have to reinstall.

> IIRC on Dell its F2 during the power-on diagnostics to reach the 
> built-in BIOS config. That is where HT is to be disabled. Works 
> exactly that way on my PowerEdge 400SC 2.8G P4. The only question is 
> whether the key is F2 to get there or not. Was F2 this afternoon on my 
> ancient Dell Optiplex 450 MHz P2 when I had to boot a DOS floppy to 
> remap some bad blocks.

Yup, mine is the same way.  Shows "Setup F2" in initial flash screen 
(and F12 for 'boot menu' which, among other things, will let you 
manually boot from a 2nd hard drive, which is nice in case the OS on 
your 1st hard drive overwrites the MBR on reinstall (*cough like 
Windows cough*).

[just arrived]
On Jan 11, 2005, at 10:18 PM, Chuck Swiger wrote:

> [ It doesn't surprise me that one would want or have to reinstall XP 
> after disabling HyperThreading.  There exist even less comprehensible 
> reasons which oblige people to reinstall Windows.... ]

Well I may reinstall Windows for other reasons, including setting up a 
FAT32 partition that I can access r/w from FreeBSD and to fix the modem 
problem... not to mention the fact that Dell installs all this crap by 
default such as McAfee Virus Scanner (which is basically just an 
attempt to get people to buy it when it "expires").

Reinstalling Windows is so common I can now pretty much time the few 
steps I have to go interactive with it without it a) sitting idle or b) 
taking me away from getting real work done.

TjL

ps - thanks to all who responded.  I'm going to disable HT, boot to 
FreeBSD and try another large file transfer and see if I see the large 
delays.  If no, I'll copy the files I need off the XP drive and 
reinstall XP.