Re: [SLUG] Re: pentium M series
On Mon, 2005-12-19 at 13:54 +1100, Jeff Waugh wrote: quote who=O Plameras Architecture wise, some changes from i386 to i586: But crucially, few of these things are interesting at the kernel level. Apps can take advantage of CPU features like these regardless of the architecture the kernel was built for. The only one that really needs kernel help is MMX/SSE stuff, but that works regardless of the architecture the kernel is built for, provided it's a recent enough kernel. As long as the kernel knows about MMX/SSE, it should do the right things with the registers even if built for '386' - it's only old kernels that don't know about MMX/SSE at all that will break. AIUI, apps that want to use those instructions should technically be checking /proc/cpuinfo for the appropriate flags in order to guarantee that the kernel won't make their data disappear, but in general it's safe anyway because everyone is running new kernels that support all the MMX/SSE features of the cpus. J. -- Jan Schmidt [EMAIL PROTECTED] It all works, but it limits Linux processes to a mere 512GB of virtual address space. Such limits are irksome to the kernel developers when the hardware can do more, and, besides, somebody is likely to release a web browser or office suite which runs into that limit in the near future. - http://lwn.net/Articles/106177/ -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
RE: [SLUG] ipv6
Anand Kumria wrote :- The site-local prefix (fe80) has been deprecated (rfc3879), instead you want IPv6 local addresses (rfc4193) which you can self-generate with tools such as: http://www.hznet.de/tools/generate-uniq-local-ipv6-unicast-addr.sh Hmm, I dropped off the IETF announce lists a few years ago so I have missed this fairly significant change. One thing I noticed though was that this script doesn't comply with the mentioned RFC. I am guessing it may have been written against an earlier draft (yep, the script says Sept. 2004). While it creates a pseudo-random address, a few problems I see are that it uses FD00::/8 as the prefix (instead of FC00::/7 which means it only tries to use half of the available space) and MD5 instead of SHA1 as the digest/randomizer. I know I am pedantic but one of the assumptions in this RFC (section 3.2.1) is that all generators of locally assigned global IDs use the same algorithm. It seems like it might be useful for me (or someone) to create an up-to-date version of this script over the Christmas break! Regards, Martin Martin Visser, CISSP Network and Security Consultant Consulting Integration Technology Solutions Group - HP Services 410 Concord Road Rhodes NSW 2138 Australia Mobile: +61-411-254-513 Fax: +61-2-9022-1800 E-mail: martin.visserAThp.com This email (including any attachments) is intended only for the use of the individual or entity named above and may contain information that is confidential, proprietary or privileged. If you are not the intended recipient, please notify HP immediately by return email and then delete the email, destroy any printed copy and do not disclose or use the information in it. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: pentium M series
Jan Schmidt was once rumoured to have said: On Mon, 2005-12-19 at 13:54 +1100, Jeff Waugh wrote: quote who=O Plameras Architecture wise, some changes from i386 to i586: But crucially, few of these things are interesting at the kernel level. Apps can take advantage of CPU features like these regardless of the architecture the kernel was built for. The only one that really needs kernel help is MMX/SSE stuff, but that works regardless of the architecture the kernel is built for, provided it's a recent enough kernel. Actually, only the SSE instruction sets require kernel support - MMX and 3dnow overload the FP registers and hence don't usually require any additional support. SSE, OTOH, uses a new set of registers for operations which the kernel needs to be aware of to handle context save/restore for. C. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: pentium M series
O Plameras was once rumoured to have said: Architecture wise, some changes from i386 to i586: 1. Native floating point in i586 (present in i486 but disabled, option to install co-processor in i386) Actually, the FPU in the i486 is enabled on the 486DX series, but not on the 486SX series. This differs from the 386 SX/DX where the 386SX had a half-width external databus vs the full 32-bit wide databus on the 386DX, but neither 386SX nor 386DX had an inbuilt FPU. The Pentium saw major improvements to overall FPU performance. When it wasn't returning incorrect values that is. Of course, this is all pretty moot since you'd have to be pretty crazy to still be using a 486 (or older) class system. However, it is important to note that there are a few 'embedded'/low performance CPUs around that don't support the Time Stamp Counter - a feature which Pentium optimised kernels generally require. 4. MMX instructions for multimedia. MMX was only introduced in the later Pentium MMX and Pentium II CPUs. After the introduction of MMX, the Pentium Pro (i686) was still available, and did not support MMX. The 'correct' method to test for MMX (and later extensions) is to check the output of the CPUID instruction. (Introduced in the late 486 families - guaranteed to be available on all Pentium class or newer systems however.) It is the CPUID instruction that the linux kernel uses to generate most of the information in /proc/cpuinfo on i386 systems. C. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: pentium M series
On Mon, 2005-12-19 at 23:40 +1100, Crossfire wrote: The 'correct' method to test for MMX (and later extensions) is to check the output of the CPUID instruction. (Introduced in the late 486 families - guaranteed to be available on all Pentium class or newer systems however.) It is the CPUID instruction that the linux kernel uses to generate most of the information in /proc/cpuinfo on i386 systems. cpuid is awesome! http://www.livejournal.com/users/kernelslacker/31732.html At least one of the comments is so totally worth reading that you should go ahead and funk on down there. /me waves at Ian -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: pentium M series
AFAIK, there have been mixed results which depend on which version of gcc you're running. While reading on the topic a few months back, the general consensus seemed to be that in general i686 (which is what I'm compiling with) actually resulted in slightly slower performance in some areas but this WAS expected to improve as gcc evolved. I think it also yields somewhat longer compile times, again this is expected to only improve. In any case, I don't think there is noticeable difference in choosing either for most desktop environments. I think of more importance is the march flag (which I've got set to pentium-m) which are supposed to include power saving optimizations. Cheers Marek On Monday 19 December 2005 12:34, Visser, Martin wrote: All, I just googled for benchmark performance linux kernel i386 versus i686 and found nothing of any import. I am just wondering if anyone has bothered doing this. It would be nice to know what the tradeoff is between performance and convenience of not needing to know the CPU architecture. Using multi-CD distros I would also choose the closest matching kernel, but for my Ubuntu installs I haven't bothered. Martin -- - Marek W -- 2b | !2b Send instant messages to your online friends http://au.messenger.yahoo.com -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: pentium M series
Hal Ashburner wrote:
On Mon, 2005-12-19 at 23:40 +1100, Crossfire wrote:
The 'correct' method to test for MMX (and later extensions) is to
check the output of the CPUID instruction. (Introduced in the late
486 families - guaranteed to be available on all Pentium class or
newer systems however.) It is the CPUID instruction that the linux
kernel uses to generate most of the information in /proc/cpuinfo on
i386 systems.
cpuid is awesome!
http://www.livejournal.com/users/kernelslacker/31732.html
A small C code to check if MMX is supported in your Linux System (x86
CPU not AMD64).
#include stdio.h
int mmx_init__(void)
{
int MMX__;
__asm__ __volatile__ (
movl $1, %%eax\n\t
cpuid\n\t
andl $0x80, %%edx\n\t
movl %%edx, %0
: =q (MMX__)
);
return MMX__;
}
int main(void)
{
if((int)mmx_init__()==0)
printf(MMX is not supported\n);
else
printf(MMX is supported\n);
return (0);
}
O Plameras
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Re: [SLUG] Re: pentium M series
On Mon, 2005-12-19 at 14:40 +1100, Ian Wienand wrote:
Mostly I think the sub-architecture is passed via different flags to
gcc, which can try to optimise the code. Talking with people from SGI
who look into that sort of thing, the benefits of even a much better
compiler fall into noise compared to things like lock contention.
Right. Which is what I've found too. Which led me to wondering: Jeff:
how do you plan to do this UP/SMP kernel efficiently? The kernel
implements spin_lock as a macro that gets compiled out when building for
UP:
/*
* If CONFIG_SMP is unset, declare the _raw_* definitions as nops
*/
#define spin_lock_init(lock)do { (void)(lock); } while(0)
#define _raw_spin_lock(lock)do { (void)(lock); } while(0)
(from include/linux/spinlock.h on 2.6.10)
(the first line is not so exciting, but the second one is pretty
important).
The corresponding code for when CONFIG_SMP is set actually implements a
spin lock, along with all the consequences you'd expect.
Does Ubuntu have a magical solution to this, or do you just execute the
extra code on UP?
Yours,
Curious in Woolloomoolloo.
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Re: [SLUG] Re: pentium M series
Right. Which is what I've found too. Which led me to wondering: Jeff: how do you plan to do this UP/SMP kernel efficiently? The kernel implements spin_lock as a macro that gets compiled out when building for UP: I've heard chat on lkml about using alternatives (the kernel ones) to do this.. basically at build time you construct a table of every spinlock call and patch them all up at CPU hotplug or kernel boot time... Sounds like magic to me... Dave. -- David Airlie, Software Engineer http://www.skynet.ie/~airlied / airlied at skynet.ie Linux kernel - DRI, VAX / pam_smb / ILUG -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
[SLUG] Any experiences with LVS for load balancing a webfarm?
Hi Sluggers, I'm just wondering if LVS is worth trying out as something to manage requests for a cluster of identical Windows-based web servers. http://www.linuxvirtualserver.org/index.html Thanks, Felix -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Any experiences with LVS for load balancing a webfarm?
i believe 2003 has its own clustering solution? Dean Felix Sheldon wrote: Hi Sluggers, I'm just wondering if LVS is worth trying out as something to manage requests for a cluster of identical Windows-based web servers. http://www.linuxvirtualserver.org/index.html Thanks, Felix -- WWW: http://deanpatrick.tk LAN: http://www.bong.com.au EMAIL: [EMAIL PROTECTED] -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Any experiences with LVS for load balancing a webfarm?
Well, yes, but unless you pay through the nose for the 'Advanced' or 'Data-center' editions I think it's fairly limited. I'd prefer something OSS that can be tweaked to do exactly what we want, without arbitrary limits designed to sell more licenses. -- Felix Dean Hamstead wrote: i believe 2003 has its own clustering solution? Dean Felix Sheldon wrote: Hi Sluggers, I'm just wondering if LVS is worth trying out as something to manage requests for a cluster of identical Windows-based web servers. http://www.linuxvirtualserver.org/index.html Thanks, Felix -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
UP/SMP switcheroo [Was: [SLUG] Re: pentium M series]
quote who=James Gregory Right. Which is what I've found too. Which led me to wondering: Jeff: how do you plan to do this UP/SMP kernel efficiently? Ben Collins (our kernel maintainer) forward ported an old 2.4 patch and put it in our git repository - maintained on kernel.org - WE ROCK! It switches locks to noops at boot time. It's not 100%, and definitely in dapper atm as early stage testing rather than an intent to ship. - Jeff -- linux.conf.au 2006: Dunedin, New Zealand http://linux.conf.au/ Blessed are the cracked, for they let in the light. - Spike Milligan -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: pentium M series
On Tue Dec 20, 2005 at 02:06:11 +, Dave Airlie wrote: Right. Which is what I've found too. Which led me to wondering: Jeff: how do you plan to do this UP/SMP kernel efficiently? The kernel implements spin_lock as a macro that gets compiled out when building for UP: I've heard chat on lkml about using alternatives (the kernel ones) to do this.. basically at build time you construct a table of every spinlock call and patch them all up at CPU hotplug or kernel boot time... Sounds like magic to me... Right, the boot time binary rewriting is a pretty cool way of diong this. This is also what we did with afterburning work, which allowed you to have one kernel that can be run on hardware and on top of L4, Xen or UML. Cheers, Benno -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Re: pentium M series
On Tue, Dec 20, 2005 at 02:06:11AM +, Dave Airlie wrote: I've heard chat on lkml about using alternatives (the kernel ones) to do this.. basically at build time you construct a table of every spinlock call and patch them all up at CPU hotplug or kernel boot time... Sounds like magic to me... No more magic than a debugger inserting breakpoints, but the thin end of a fairly nasty wedge -- debugging the kernel is already hard enough without ever being able to ascertain exactly what is executing! -i signature.asc Description: Digital signature -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Any experiences with LVS for load balancing a webfarm?
depends what you want to achieve then round robin dns can be very effective in many circumstances. Dean Felix Sheldon wrote: Well, yes, but unless you pay through the nose for the 'Advanced' or 'Data-center' editions I think it's fairly limited. I'd prefer something OSS that can be tweaked to do exactly what we want, without arbitrary limits designed to sell more licenses. -- WWW: http://deanpatrick.tk LAN: http://www.bong.com.au EMAIL: [EMAIL PROTECTED] -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
[SLUG] Palm handheld repair?
I finally got my Palm handheld synchronising nicely in Linux and then its touchscreen stopped working properly. What I've heard about Palm Australia's service makes me want to avoid it for repairs if possible. Does anyone know of a reputable Palm repairer in the Sydney area? -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
RE: [SLUG] Palm handheld repair?
I finally got my Palm handheld synchronising nicely in Linux and then its touchscreen stopped working properly. What I've heard about Palm Australia's service makes me want to avoid it for repairs if possible. Does anyone know of a reputable Palm repairer in the Sydney area? I swapped my T3 for a reconditioned model under warranty without any issues, but this was a couple of years ago. I've not heard of any local Palm repairers, but http://www.auspug.org/ is probably the best place to ask. Are you sure that touchscreen stopped working properly == needs repair? A reset and/or recalibration may suffice. HTH, - Rog -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Any experiences with LVS for load balancing a webfarm?
looking through the lvs website it seems the project is more oriented
around the load balancer. which would mean the server OS and software
would be irrelevant. this sort of arrangement can be acommplished with
lots of various hardware slash applicance type devices. however the
price difference is fairly obvious.
http://www.austintek.com/LVS/LVS-HOWTO/HOWTO/
in the howto there is mention of using freebsd and win2k servers.
the author mentions a successfull testbed install load balancing
terminal services servers. the load balancer has been ported to
freebsd it would seem.
im assuming you want to load balance websites?
it shouldnt be a huge drama to arrange to keep the content on all
three in sync (dfs or batch files if you are like that). you
could even use cvs/svn/vss which seems to be a good solution in
some circumstances. a database driven website would simplify things
enormously.
just have
{WWW cloud}
|
[load balancer]
| | | | | |
[servers a plenty]
| | | | | |
(db server)
thats a horrible diagram =(
Dean
Felix Sheldon wrote:
Well, yes, but unless you pay through the nose for the 'Advanced' or
'Data-center' editions I think it's fairly limited. I'd prefer something
OSS that can be tweaked to do exactly what we want, without arbitrary
limits designed to sell more licenses.
--
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LAN: http://www.bong.com.au
EMAIL: [EMAIL PROTECTED]
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Re: Re: [SLUG] Any experiences with LVS for load balancing a webfarm?
Thanks Dean.
Yep, it does seem that it's possible. It also seems to allow a custom script
for checking which servers are up, which is probably going to be more reliable
than round-robin DNS.
That diagram is exactly what we want, there is a DB backend, so there's no real
drama with shared data, and ssh is probably good enough to keep the semi-static
stuff up to date.
I'll have to try it out I suppose.
--
Felix
Dean Hamstead [EMAIL PROTECTED] wrote:
looking through the lvs website it seems the project is more oriented
around the load balancer. which would mean the server OS and software
would be irrelevant. this sort of arrangement can be acommplished with
lots of various hardware slash applicance type devices. however the
price difference is fairly obvious.
http://www.austintek.com/LVS/LVS-HOWTO/HOWTO/
in the howto there is mention of using freebsd and win2k servers.
the author mentions a successfull testbed install load balancing
terminal services servers. the load balancer has been ported to
freebsd it would seem.
im assuming you want to load balance websites?
it shouldnt be a huge drama to arrange to keep the content on all
three in sync (dfs or batch files if you are like that). you
could even use cvs/svn/vss which seems to be a good solution in
some circumstances. a database driven website would simplify things
enormously.
just have
{WWW cloud}
|
[load balancer]
| | | | | |
[servers a plenty]
| | | | | |
(db server)
thats a horrible diagram =(
Dean
Felix Sheldon wrote:
Well, yes, but unless you pay through the nose for the 'Advanced' or
'Data-center' editions I think it's fairly limited. I'd prefer
something
OSS that can be tweaked to do exactly what we want, without arbitrary
limits designed to sell more licenses.
--
WWW: http://deanpatrick.tk
LAN: http://www.bong.com.au
EMAIL: [EMAIL PROTECTED]
--
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Re: [SLUG] Any experiences with LVS for load balancing a webfarm?
should be an interesting project. good luck with it. Dean [EMAIL PROTECTED] wrote: Thanks Dean. Yep, it does seem that it's possible. It also seems to allow a custom script for checking which servers are up, which is probably going to be more reliable than round-robin DNS. That diagram is exactly what we want, there is a DB backend, so there's no real drama with shared data, and ssh is probably good enough to keep the semi-static stuff up to date. I'll have to try it out I suppose. -- WWW: http://deanpatrick.tk LAN: http://www.bong.com.au EMAIL: [EMAIL PROTECTED] -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
[SLUG] Palm handheld repair?
Roger, Many thanks for your reply post. I've re-posted my query on the AUSPUG list. I wasn't aware of AUSPUG until you mentioned it. As to a recalibration following reset, unfortunately, I've tried that, both with the built-in digitiser and with a 3rd party app (digifix?) said to be better than the built-in one, but without success. Thanks again, Leslie -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
