Re: [PATCH 0/6] Reduce compaction scanning and lock contention
From: Richard Davies <hidden>
Date: 2012-09-21 09:13:49
Also in:
kvm, lkml, qemu-devel
Hi Mel,
Thank you for this series. I have applied on clean 3.6-rc5 and tested, and
it works well for me - the lock contention is (still) gone and
isolate_freepages_block is much reduced.
Here is a typical test with these patches:
# grep -F '[k]' report | head -8
65.20% qemu-kvm [kernel.kallsyms] [k] clear_page_c
2.18% qemu-kvm [kernel.kallsyms] [k] isolate_freepages_block
1.56% qemu-kvm [kernel.kallsyms] [k] _raw_spin_lock
1.40% qemu-kvm [kernel.kallsyms] [k] svm_vcpu_run
1.38% swapper [kernel.kallsyms] [k] default_idle
1.35% qemu-kvm [kernel.kallsyms] [k] get_page_from_freelist
0.74% ksmd [kernel.kallsyms] [k] memcmp
0.72% qemu-kvm [kernel.kallsyms] [k] free_pages_prepare
I did manage to get a couple which were slightly worse, but nothing like as
bad as before. Here are the results:
# grep -F '[k]' report | head -8
45.60% qemu-kvm [kernel.kallsyms] [k] clear_page_c
11.26% qemu-kvm [kernel.kallsyms] [k] isolate_freepages_block
3.21% qemu-kvm [kernel.kallsyms] [k] _raw_spin_lock
2.27% ksmd [kernel.kallsyms] [k] memcmp
2.02% swapper [kernel.kallsyms] [k] default_idle
1.58% qemu-kvm [kernel.kallsyms] [k] svm_vcpu_run
1.30% qemu-kvm [kernel.kallsyms] [k] _raw_spin_lock_irqsave
1.09% qemu-kvm [kernel.kallsyms] [k] get_page_from_freelist
# grep -F '[k]' report | head -8
61.29% qemu-kvm [kernel.kallsyms] [k] clear_page_c
4.52% qemu-kvm [kernel.kallsyms] [k] _raw_spin_lock_irqsave
2.64% qemu-kvm [kernel.kallsyms] [k] copy_page_c
1.61% swapper [kernel.kallsyms] [k] default_idle
1.57% qemu-kvm [kernel.kallsyms] [k] _raw_spin_lock
1.18% qemu-kvm [kernel.kallsyms] [k] get_page_from_freelist
1.18% qemu-kvm [kernel.kallsyms] [k] isolate_freepages_block
1.11% qemu-kvm [kernel.kallsyms] [k] svm_vcpu_run
I will follow up with the detailed traces for these three tests.
Thank you!
Richard.
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