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zachula
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PostPosted: Fri Aug 12, 2005 12:26 am    Post subject: Removing SMP on Ultra10 single proc Reply with quote

Trying to tweak things down to the smallest, fastest kernel I can. For some reason I cannot get the kernel to compile correctly without SMP. This is really my first foray into kernel optimization and I have already destroyed one kernel in my noobishness because I overwrote my existing working kernel.....luckilly the skills I learned during installation were used and I chrooted back in and rebuilt my kernel(I was smart enough to back my original working config up)


So now after some searching on the forums but not really finding much I ask, do I have to have SMP in? I don't use it and probably never will on this machine. I have already dumped most of the things that will never touch this box(SCSI support, Firewire, raid controllers and the like) because I figure if I do ever add hardware to this machine(why??) then I will end up recompiling my kernel anyways. This is good practice anyways.

oh and I am running 2.4.29 sparc64 on a 300mhz Sparc IIi Ultra10. Any tips?


Maybe even some general knowledge....like I know the difference between a modularized and a monolithic kernel and I am pretty sure I understand the pros and cons for each one. ie monolithic means all drivers compiled in = faster operation in most cases but less flexible and tolerant of hw changes also typically faster compile times whereas modular kernels are a little slower but much more flexible when it comes to hw support on the fly and they take longer to compile.(if I am wrong please please point out the error in my ways so I may be so enlightened)

oh yeah....do I need to update the system.map file every time I recompile?
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Ferris
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PostPosted: Fri Aug 12, 2005 11:39 am    Post subject: Reply with quote

On a U10, you will never use SMP because it is not mulit-processor capable. Off hand, I can't think of any reason why you should have to compile it in; last I knew the live CD distributions had both SMP and single processor kernels on them.

Using modules is a matter of taste. I always build a lot of things as modules, but they tend to be for capabilities that I don't actually ever care about. I don't know of any particular performance issues. (Their greatest use has been to keep the size of the kernel below a magic upper bound, but with current version of SILO, that upper bound is now huge.)

System.map gets rewritten automatically every time you build and install a kernel, whether you like it or not. I usually copy it into the /boot partition along with the kernel and it's .config file, but the system doesn't require it. What you must do is remember to 'make modules_install'.

Regards,
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zachula
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PostPosted: Fri Aug 12, 2005 3:44 pm    Post subject: Reply with quote

My thoughts exactly. I tried it a couple times and it would give some strange error during compile

Code:

In file included from /usr/src/linux-2.4.29-sparc/include/linux/sched.h:23,
                 from /usr/src/linux-2.4.29-sparc/include/linux/mm.h:4,
                 from sys.c:9:
/usr/src/linux-2.4.29-sparc/include/linux/smp.h:80:1: warning: "smp_num_cpus" redefined
In file included from /usr/src/linux-2.4.29-sparc/include/linux/modversions.h:281,
                 from /usr/src/linux-2.4.29-sparc/include/linux/module.h:22,
                 from sys.c:8:
/usr/src/linux-2.4.29-sparc/include/linux/modules/sparc64_ksyms.ver:26:1: warning: this is the location of the previous definition
In file included from /usr/src/linux-2.4.29-sparc/include/linux/sched.h:23,
                 from /usr/src/linux-2.4.29-sparc/include/linux/mm.h:4,
                 from sys.c:9:
/usr/src/linux-2.4.29-sparc/include/linux/smp.h:87:1: warning: "smp_call_function" redefined
In file included from /usr/src/linux-2.4.29-sparc/include/linux/modversions.h:281,
                 from /usr/src/linux-2.4.29-sparc/include/linux/module.h:22,
                 from sys.c:8:
/usr/src/linux-2.4.29-sparc/include/linux/modules/sparc64_ksyms.ver:32:1: warning: this is the location of the previous definition
In file included from /usr/src/linux-2.4.29-sparc/include/linux/mm.h:4,
                 from sys.c:9:
/usr/src/linux-2.4.29-sparc/include/linux/sched.h:162:1: warning: "set_cpus_allowed" redefined
In file included from /usr/src/linux-2.4.29-sparc/include/linux/modversions.h:180,
                 from /usr/src/linux-2.4.29-sparc/include/linux/module.h:22,
                 from sys.c:8:

My current config only differs from this one in that SMP was enabled in the last one that compiled successfully(NOT a module which I think is a mistake I may have made so looks like I get more practice with menuconfig :-) *EDIT* looks like SMP is either there or its not....having it be a module is not an option*EDIT*

Ultimately when SMP is left out, the compile exits about 5 minutes into it with the following:
Code:

make[2]: *** [ksyms.o] Error 1
make[2]: Leaving directory `/usr/src/linux-2.4.29-sparc/kernel'
make[1]: *** [first_rule] Error 2
make[1]: Leaving directory `/usr/src/linux-2.4.29-sparc/kernel'
make: *** [_dir_kernel] Error 2

Just wondering if anyone else has had this problem or has come to the same conclusions that I have. Ultimately my goal is to have a kernel with support for only those services/devices which I plan to be using....that is after all one of the benefits to "rolling" your own.
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gust4voz
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PostPosted: Fri Aug 12, 2005 5:11 pm    Post subject: Reply with quote

Did you make dep before recompiling after changing the configuration option?
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zachula
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PostPosted: Tue Aug 16, 2005 6:17 pm    Post subject: Reply with quote

gust4voz wrote:
Did you make dep before recompiling after changing the configuration option?



Yes.

I used
Code:
 make dep && make clean vmlinux image modules modules_install
to compile my kernel both times.

Last edited by zachula on Tue Aug 16, 2005 8:31 pm; edited 1 time in total
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i-right-i
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PostPosted: Tue Aug 16, 2005 8:02 pm    Post subject: Reply with quote

I just compiled a non-smp kernel on an intital install of a Ultra 5 and it is running like a top. So it can be done.

I am using sparc sources 2.4.31 if that makes any difference.

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PostPosted: Mon Aug 22, 2005 11:58 pm    Post subject: Reply with quote

Quote:

I used
Code:
make dep && make clean vmlinux image modules modules_install

to compile my kernel both times.


Well that's probably your problem... you're doing 'make clean' AFTER 'make dep'... try something like this:
Code:
make clean && make dep vmlinux image modules modules_install
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Nijinski
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PostPosted: Tue Aug 23, 2005 6:20 pm    Post subject: Reply with quote

Someone should really look at the install guide then, that's the order it says to do things there. 8O
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i-right-i
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PostPosted: Tue Aug 23, 2005 7:49 pm    Post subject: Reply with quote

When I did mine, I did mine according to the 2005.1 guide. I haven't looked but if they are the same, which I think they are, then I doubt running a make clean after make dep is the issue.

My Ultra 5 and Ultra 10 have almost exactly the same hardware. They have the same CPU, Ram, Chipset, SoundChip.

Did you try 2.4.31 sparc sources?

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Ferris
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PostPosted: Tue Aug 23, 2005 11:14 pm    Post subject: Reply with quote

zachula,
Is this still a problem? If so, you might try joining theIRC Freenode #gentoo-sparc channel and asking for a working kernel .config file for a U10 (or for a U5). Or, ask someone in this forum thread for a copy of a working .config. I am not running a U10, but people responding to you are, and certainly people in #gentoo-sparc channel use them, too. Often, people share such .config files when you ask for examples.

Regards,
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ginodouglas
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PostPosted: Wed Aug 24, 2005 1:05 pm    Post subject: Removing SMP on Ultra10 single proc Reply with quote

I coudn't make a useful kernel from sparc-sources 2.4.31, it always panic at boot. I tried to remove SMP and it didn't compile, got a lot of errors. I put back SMP but with only 2 CPU's and now it is working fine.

The box is an Ultra 10, 333MHz, 512MB.

Gino
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i-right-i
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PostPosted: Fri Aug 26, 2005 4:08 pm    Post subject: Reply with quote

I will copy my kenerl config tonight when I get home, the box has moved there and hes become a firewall now.

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