From: Paul Mackerras <paulus@ozlabs.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: benh@kernel.crashing.org, mpe@ellerman.id.au,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 00/16] Remove hash page table slot tracking from linux PTE
Date: Fri, 27 Oct 2017 16:41:36 +1100 [thread overview]
Message-ID: <20171027054136.GC27483@fergus.ozlabs.ibm.com> (raw)
In-Reply-To: <adf2d270-29df-701f-206e-0d8a35084e47@linux.vnet.ibm.com>
On Fri, Oct 27, 2017 at 10:57:13AM +0530, Aneesh Kumar K.V wrote:
>
>
> On 10/27/2017 10:04 AM, Paul Mackerras wrote:
> >How do we interpret these numbers? Are they times, or speed? Is
> >larger better or worse?
>
> Sorry for not including the details. They are time in seconds. Test case is
> a modified mmap_bench included in powerpc/selftest.
>
> >
> >Can you give us the mean and standard deviation for each set of 5
> >please?
> >
>
> powernv without patch
> median= 51.432255
> stdev = 0.370835
>
> with patch
> median = 50.739922
> stdev = 0.06419662
>
> pseries without patch
> median = 116.617884
> stdev = 3.04531023
>
> with patch no hcall
> median = 119.42494
> stdev = 0.85874552
>
> with patch and hcall
> median = 117.735808
> stdev = 2.7624151
So on powernv, the patch set *improves* performance by about 1.3%
(almost 2 standard deviations). Do we know why that is?
On pseries, performance is about 2.4% worse without new hcalls, but
that is less than 1 standard deviation. With new hcalls, performance
is 0.95% worse, only a third of a standard deviation. I think we need
to do more measurements to try to get a more accurate picture here.
Were the pseries numbers done on KVM or PowerVM? Could you do a set
of measurements on the other one too please? (I assume the numbers
with the new hcall were done on KVM, and can't be done on PowerVM.)
Paul.
next prev parent reply other threads:[~2017-10-27 5:41 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-27 4:08 [PATCH 00/16] Remove hash page table slot tracking from linux PTE Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 01/16] powerpc/mm/hash: Remove the superfluous bitwise operation when find hpte group Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 02/16] powerpc/mm: Update native_hpte_find to return hash pte Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 03/16] powerpc/pseries: Update hpte find helper to take hash value Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 04/16] powerpc/mm: Add hash invalidate callback Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 05/16] powerpc/mm: use hash_invalidate for __kernel_map_pages() Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 06/16] powerpc/mm: Switch flush_hash_range to not use slot Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 07/16] powerpc/mm: Add hash updatepp callback Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 08/16] powerpc/mm/hash: Don't track hash pte slot number in linux page table Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 09/16] powerpc/mm: Add new firmware feature HASH API Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 10/16] powerpc/kvm/hash: Implement HASH_REMOVE hcall Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 11/16] powerpc/kvm/hash: Implement HASH_PROTECT hcall Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 12/16] powerpc/kvm/hash: Implement HASH_BULK_REMOVE hcall Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 13/16] powerpc/mm/pseries: Use HASH_PROTECT hcall in guest Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 14/16] powerpc/mm/pseries: Use HASH_REMOVE " Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 15/16] powerpc/mm/pseries: Move slot based bulk remove to helper Aneesh Kumar K.V
2017-10-27 4:08 ` [PATCH 16/16] powerpc/mm/pseries: Use HASH_BULK_REMOVE hcall in guest Aneesh Kumar K.V
2017-10-27 4:34 ` [PATCH 00/16] Remove hash page table slot tracking from linux PTE Paul Mackerras
2017-10-27 5:27 ` Aneesh Kumar K.V
2017-10-27 5:41 ` Paul Mackerras [this message]
2017-10-30 7:57 ` Aneesh Kumar K.V
2017-10-30 11:49 ` Aneesh Kumar K.V
2017-10-30 13:14 ` Aneesh Kumar K.V
2017-10-30 13:49 ` Aneesh Kumar K.V
2017-11-21 8:41 ` Aneesh Kumar K.V
2017-10-28 22:35 ` Ram Pai
2017-10-29 14:05 ` Aneesh Kumar K.V
2017-10-29 22:04 ` Paul Mackerras
2017-10-30 0:51 ` Ram Pai
2017-11-01 4:46 ` Michael Ellerman
2017-11-01 11:02 ` Paul Mackerras
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