From: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
To: Avi Kivity <avi@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>,
peterz@infradead.org, linux-kernel@vger.kernel.org,
vatsa@linux.vnet.ibm.com, bharata@linux.vnet.ibm.com
Subject: Re: [RFC PATCH 0/4] Gang scheduling in CFS
Date: Fri, 23 Dec 2011 08:50:04 +0530 [thread overview]
Message-ID: <877h1o9dp7.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <4EF1B85F.7060105@redhat.com>
On Wed, 21 Dec 2011 12:43:43 +0200, Avi Kivity <avi@redhat.com> wrote:
> On 12/21/2011 12:39 PM, Nikunj A Dadhania wrote:
> > On Mon, 19 Dec 2011 12:23:26 +0100, Ingo Molnar <mingo@elte.hu> wrote:
> > >
> > > * Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com> wrote:
> > >
> > > So could we please approach this from the benchmarked workload
> > > angle first? The highest improvement is in ebizzy:
> > >
> > > > ebizzy 2vm (improved 15 times, i.e. 1520%)
> > >
> > > What's behind this huge speedup? Does ebizzy use user-space
> > > spinlocks perhaps? Could we do something on the user-space side
> > > to get a similar speedup?
> > >
> > This is from the perf run on the host:
> >
> > Baseline:
> >
> > 16.22% qemu-kvm [kvm_intel] [k] free_kvm_area
> > 8.27% qemu-kvm [kvm] [k] start_apic_timer
> > 7.53% qemu-kvm [kvm] [k] kvm_put_guest_fpu
> >
> > Gang:
> >
> > 24.44% qemu-kvm [kvm_intel] [k] free_kvm_area
> > 13.42% qemu-kvm [kvm] [k] start_apic_timer
> > 9.91% qemu-kvm [kvm] [k] kvm_put_guest_fpu
> >
> > Ingo, Avi, I am not getting anything obvious from this. Any ideas?
> >
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.
Regards
Nikunj
next prev parent reply other threads:[~2011-12-23 3:24 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-19 8:33 Nikunj A. Dadhania
2011-12-19 8:34 ` [RFC PATCH 1/4] sched: Adding cpu.gang file to cpu cgroup Nikunj A. Dadhania
2011-12-19 8:34 ` [RFC PATCH 2/4] sched: Adding gang scheduling infrastrucure Nikunj A. Dadhania
2011-12-19 15:51 ` Peter Zijlstra
2011-12-19 16:51 ` Peter Zijlstra
2011-12-20 1:43 ` Nikunj A Dadhania
2011-12-20 1:39 ` Nikunj A Dadhania
2011-12-19 8:34 ` [RFC PATCH 3/4] sched: Gang using set_next_buddy Nikunj A. Dadhania
2011-12-19 8:35 ` [RFC PATCH 4/4] sched:Implement set_gang_buddy Nikunj A. Dadhania
2011-12-19 15:51 ` Peter Zijlstra
2011-12-20 1:43 ` Nikunj A Dadhania
2011-12-26 2:30 ` Nikunj A Dadhania
2011-12-19 11:23 ` [RFC PATCH 0/4] Gang scheduling in CFS Ingo Molnar
2011-12-19 11:44 ` Avi Kivity
2011-12-19 11:50 ` Nikunj A Dadhania
2011-12-19 11:59 ` Avi Kivity
2011-12-19 12:06 ` Nikunj A Dadhania
2011-12-19 12:50 ` Avi Kivity
2011-12-19 13:09 ` Nikunj A Dadhania
2011-12-19 11:45 ` Nikunj A Dadhania
2011-12-19 13:22 ` Nikunj A Dadhania
2011-12-19 16:28 ` Ingo Molnar
2011-12-21 10:39 ` Nikunj A Dadhania
2011-12-21 10:43 ` Avi Kivity
2011-12-23 3:20 ` Nikunj A Dadhania [this message]
2011-12-23 10:36 ` Ingo Molnar
2011-12-25 10:58 ` Avi Kivity
2011-12-25 15:45 ` Avi Kivity
2011-12-26 3:14 ` Nikunj A Dadhania
2011-12-26 9:05 ` Avi Kivity
2011-12-26 11:33 ` Nikunj A Dadhania
2011-12-26 11:41 ` Avi Kivity
2011-12-27 1:47 ` Nikunj A Dadhania
2011-12-27 9:15 ` Avi Kivity
2011-12-27 10:24 ` Nikunj A Dadhania
2011-12-27 3:15 ` Nikunj A Dadhania
2011-12-27 9:17 ` Avi Kivity
2011-12-27 9:44 ` Nikunj A Dadhania
2011-12-27 9:51 ` Avi Kivity
2011-12-27 10:10 ` Nikunj A Dadhania
2011-12-27 10:34 ` Avi Kivity
2011-12-27 10:43 ` Nikunj A Dadhania
2011-12-27 10:53 ` Avi Kivity
2011-12-30 9:51 ` Ingo Molnar
2011-12-30 10:10 ` Nikunj A Dadhania
2011-12-31 2:21 ` Nikunj A Dadhania
2012-01-02 4:20 ` Nikunj A Dadhania
2012-01-02 9:39 ` Avi Kivity
2012-01-02 10:22 ` Nikunj A Dadhania
2012-01-02 9:37 ` Avi Kivity
2012-01-02 10:30 ` Nikunj A Dadhania
2012-01-02 13:33 ` Avi Kivity
2012-01-04 10:52 ` Nikunj A Dadhania
2012-01-04 14:41 ` Avi Kivity
2012-01-04 14:56 ` Srivatsa Vaddagiri
2012-01-04 17:13 ` Avi Kivity
2012-01-05 6:57 ` Nikunj A Dadhania
2012-01-04 16:47 ` Rik van Riel
2012-01-04 17:16 ` Avi Kivity
2012-01-04 20:56 ` Rik van Riel
2012-01-04 21:31 ` Peter Zijlstra
2012-01-04 21:41 ` Avi Kivity
2012-01-05 9:10 ` Ingo Molnar
2012-02-20 8:08 ` Nikunj A Dadhania
2012-02-20 8:14 ` Ingo Molnar
2012-02-20 10:51 ` Peter Zijlstra
2012-02-20 11:53 ` Nikunj A Dadhania
2012-02-20 12:02 ` Srivatsa Vaddagiri
2012-02-20 12:14 ` Peter Zijlstra
2012-01-05 2:10 ` Nikunj A Dadhania
2011-12-19 15:51 ` Peter Zijlstra
2011-12-19 16:09 ` Alan Cox
2011-12-19 22:10 ` Benjamin Herrenschmidt
2011-12-20 1:56 ` Nikunj A Dadhania
2011-12-20 8:52 ` Jeremy Fitzhardinge
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