Messages in this thread | | | Date | Fri, 23 Dec 2011 11:36:20 +0100 | From | Ingo Molnar <> | Subject | Re: [RFC PATCH 0/4] Gang scheduling in CFS |
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* Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> wrote:
> Here some interesting perf reports from inside the guest: > > Baseline: > 29.79% ebizzy [kernel.kallsyms] [k] native_flush_tlb_others > 18.70% ebizzy libc-2.12.so [.] __GI_memcpy > 7.23% ebizzy [kernel.kallsyms] [k] get_page_from_freelist > 5.38% ebizzy [kernel.kallsyms] [k] __do_page_fault > 4.50% ebizzy [kernel.kallsyms] [k] ____pagevec_lru_add > 3.58% ebizzy [kernel.kallsyms] [k] default_send_IPI_mask_logical > 3.26% ebizzy [kernel.kallsyms] [k] native_flush_tlb_single > 2.82% ebizzy [kernel.kallsyms] [k] handle_pte_fault > 2.16% ebizzy [kernel.kallsyms] [k] kunmap_atomic > 2.10% ebizzy [kernel.kallsyms] [k] _spin_unlock_irqrestore > 1.90% ebizzy [kernel.kallsyms] [k] down_read_trylock > 1.65% ebizzy [kernel.kallsyms] [k] __mem_cgroup_commit_charge.clone.4 > 1.60% ebizzy [kernel.kallsyms] [k] up_read > 1.24% ebizzy [kernel.kallsyms] [k] __alloc_pages_nodemask > > Gang: > 22.53% ebizzy libc-2.12.so [.] __GI_memcpy > 9.73% ebizzy [kernel.kallsyms] [k] ____pagevec_lru_add > 8.22% ebizzy [kernel.kallsyms] [k] get_page_from_freelist > 7.80% ebizzy [kernel.kallsyms] [k] default_send_IPI_mask_logical > 7.68% ebizzy [kernel.kallsyms] [k] native_flush_tlb_others > 6.22% ebizzy [kernel.kallsyms] [k] __do_page_fault > 5.54% ebizzy [kernel.kallsyms] [k] native_flush_tlb_single > 4.44% ebizzy [kernel.kallsyms] [k] _spin_unlock_irqrestore > 2.90% ebizzy [kernel.kallsyms] [k] kunmap_atomic > 2.78% ebizzy [kernel.kallsyms] [k] __mem_cgroup_commit_charge.clone.4 > 2.76% ebizzy [kernel.kallsyms] [k] handle_pte_fault > 2.16% ebizzy [kernel.kallsyms] [k] __mem_cgroup_uncharge_common > 1.59% ebizzy [kernel.kallsyms] [k] down_read_trylock > 1.43% ebizzy [kernel.kallsyms] [k] up_read > > I see the main difference between both the reports is: > native_flush_tlb_others.
So it would be important to figure out why ebizzy gets into so many TLB flushes and why gang scheduling makes it go away.
Thanks,
Ingo
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