[PATCH 00/10] x86: Reduce memory and intra-node effects with large count NR_CPUs

From: travis
Date: Sun Jan 13 2008 - 13:36:45 EST



This patchset addresses the kernel bloat that occurs when NR_CPUS is increased.
The memory numbers below are with NR_CPUS = 1024 which I've been testing (4 and
32 real processors, the rest "possible" using the additional_cpus start option.)
These changes are all specific to the x86 architecture, non-arch specific
changes will follow.

Based on 2.6.24-rc6-mm1

Signed-off-by: Mike Travis <travis@xxxxxxx>
Reviewed-by: Christoph Lameter <clameter@xxxxxxx>
---

The following columns are using the default x86_64 config with no modules.
32cpus is the default NR_CPUS, 1kcpus-before has NR_CPUS = 1024, and
1kcpus-after is after applying this patch.

As noticeable below there's still plenty of room for improvement... ;-)

32cpus 1kcpus-before 1kcpus-after
228 .altinstr_repl +0 .altinstr_repl +0 .altinstr_repl
1219 .altinstructio +0 .altinstructio +0 .altinstructio
717512 .bss +1542784 .bss -147456 .bss
61374 .comment +0 .comment +0 .comment
16 .con_initcall. +0 .con_initcall. +0 .con_initcall.
425256 .data +20224 .data -1024 .data
178688 .data.cachelin +12898304 .data.cachelin +0 .data.cachelin
8192 .data.init_tas +0 .data.init_tas +0 .data.init_tas
4096 .data.page_ali +0 .data.page_ali +0 .data.page_ali
27008 .data.percpu +128768 .data.percpu +128 .data.percpu
43904 .data.read_mos +8707872 .data.read_mos -4096 .data.read_mos
4 .data_nosave +0 .data_nosave +0 .data_nosave
5141 .exit.text +9 .exit.text -1 .exit.text
138480 .init.data +992 .init.data +3616 .init.data
133 .init.ramfs +0 .init.ramfs +1 .init.ramfs
3192 .init.setup +0 .init.setup +0 .init.setup
159754 .init.text +891 .init.text +13 .init.text
2288 .initcall.init +0 .initcall.init +0 .initcall.init
8 .jiffies +0 .jiffies +0 .jiffies
4512 .pci_fixup +0 .pci_fixup +0 .pci_fixup
1314438 .rodata +1312 .rodata -552 .rodata
36552 .smp_locks +256 .smp_locks +0 .smp_locks
3971848 .text +12992 .text +1781 .text
3368 .vdso +0 .vdso +0 .vdso
4 .vgetcpu_mode +0 .vgetcpu_mode +0 .vgetcpu_mode
218 .vsyscall_0 +0 .vsyscall_0 +0 .vsyscall_0
52 .vsyscall_1 +0 .vsyscall_1 +0 .vsyscall_1
91 .vsyscall_2 +0 .vsyscall_2 +0 .vsyscall_2
8 .vsyscall_3 +0 .vsyscall_3 +0 .vsyscall_3
54 .vsyscall_fn +0 .vsyscall_fn +0 .vsyscall_fn
80 .vsyscall_gtod +0 .vsyscall_gtod +0 .vsyscall_gtod
39480 __bug_table +0 __bug_table +0 __bug_table
16320 __ex_table +0 __ex_table +0 __ex_table
9160 __param +0 __param +0 __param
7172678 Total +23314404 Total -147590 Total

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