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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	paulus@samba.org, mpe@ellerman.id.au
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 19/31] powerpc/mm: Convert 4k hash insert to C
Date: Tue, 29 Sep 2015 13:43:43 +0530	[thread overview]
Message-ID: <874midprrc.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <1442823396.2819.2.camel@kernel.crashing.org>

Benjamin Herrenschmidt <benh@kernel.crashing.org> writes:

> On Mon, 2015-09-21 at 12:10 +0530, Aneesh Kumar K.V wrote:
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
>> ---
>>  arch/powerpc/mm/Makefile        |   3 +
>>  arch/powerpc/mm/hash64_64k.c    | 204 +++++++++++++++++++++
>>  arch/powerpc/mm/hash_low_64.S   | 380 ------------------------------
>> ----------
>>  arch/powerpc/mm/hash_utils_64.c |   4 +-
>>  4 files changed, 210 insertions(+), 381 deletions(-)
>>  create mode 100644 arch/powerpc/mm/hash64_64k.c
>
> Did you check if there was any measurable performance difference ?
>


I looked at the performance number with and without patch. I don't see much
impact in the numbers. We do have a path lengh increase ( I measured this
using systemsim)

Path length __hash_page_4k
with patch: 196
without patch: 142

Path length __hash_page_64k
with patch: 219
without patch: 154


But even if we have a path lengh increase of around 50 instructions. We don't see
the impact when running workload. I tried the kernelbuild test. 

With THP enabled (which is default) we see an improvement. I haven't fully looked at
the reason. This could be due to reduced contention of ptl lock. __hash_thp_page is
already a C code.

make -j64 vmlinux modules 
With fix:
---------
real    1m35.509s
user    56m8.565s
sys     4m34.973s

real    1m32.174s
user    57m2.336s
sys     4m39.142s

Without fix:
---------------
real    1m37.703s
user    58m50.783s
sys     7m52.440s


real    1m37.890s
user    57m55.445s
sys     7m50.501s


THP disabled:

make -j64 vmlinux modules 
With fix:
---------
real    1m37.197s
user    58m28.672s
sys     7m58.188s

real    1m44.638s
user    58m37.551s
sys     7m53.960s

Without fix:
------------
real    1m41.224s
user    58m46.944s
sys     7m49.714s


real    1m42.585s
user    59m14.019s
sys     7m52.714s


-aneesh

  parent reply	other threads:[~2015-09-29  8:15 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-21  6:40 [PATCH 00/31] powerpc/mm: Update page table format for book3s 64 Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 01/31] powerpc/mm: move pte headers to book3s directory Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 02/31] powerpc/mm: move pte headers to book3s directory (part 2) Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 03/31] powerpc/mm: make a separate copy for book3s Aneesh Kumar K.V
2015-09-21 21:58   ` Scott Wood
2015-09-22  6:42     ` Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 04/31] powerpc/mm: make a separate copy for book3s (part 2) Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 05/31] powerpc/mm: Move hash specific pte width and other defines to book3s Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 06/31] powerpc/mm: Delete booke bits from book3s Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 07/31] powerpc/mm: Don't have generic headers introduce functions touching pte bits Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 08/31] powerpc/mm: Drop pte-common.h from BOOK3S 64 Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 09/31] powerpc/mm: Don't use pte_val as lvalue Aneesh Kumar K.V
2015-09-22  2:22   ` Scott Wood
2015-09-22  6:44     ` Aneesh Kumar K.V
2015-09-22  6:46       ` Scott Wood
2015-09-21  6:40 ` [PATCH 10/31] powerpc/mm: Don't use pmd_val, pud_val and pgd_val " Aneesh Kumar K.V
2015-09-22  2:23   ` Scott Wood
2015-09-22  6:45     ` Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 11/31] powerpc/mm: Move hash64 PTE bits from book3s/64/pgtable.h to hash.h Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 12/31] powerpc/mm: Move PTE bits from generic functions to hash64 functions Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 13/31] powerpc/booke: Move booke headers (part 1) Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 14/31] powerpc/booke: Move booke headers (part 2) Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 15/31] powerpc/booke: Move booke headers (part 3) Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 16/31] powerpc/booke: Move booke headers (part 4) Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 17/31] powerpc/booke: Move booke headers (part 5) Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 18/31] powerpc/mm: Increase the pte frag size Aneesh Kumar K.V
2015-09-21  8:14   ` Benjamin Herrenschmidt
2015-09-21  8:45     ` Aneesh Kumar K.V
2015-09-21 11:06       ` Benjamin Herrenschmidt
2015-09-21 11:53         ` Aneesh Kumar K.V
2015-09-23 21:37           ` Benjamin Herrenschmidt
2015-09-28  4:55             ` Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 19/31] powerpc/mm: Convert 4k hash insert to C Aneesh Kumar K.V
2015-09-21  8:16   ` Benjamin Herrenschmidt
2015-09-21  8:57     ` Aneesh Kumar K.V
2015-09-29  8:13     ` Aneesh Kumar K.V [this message]
2015-09-21  6:40 ` [PATCH 20/31] powerpc/mm: update __real_pte to take address as argument Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 21/31] powerpc/mm: make pte page hash index slot 8 bits Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 22/31] powerpc/mm: Don't track subpage valid bit in pte_t Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 23/31] powerpc/mm: Increase the width of #define Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 24/31] powerpc/mm: Convert __hash_page_64K to C Aneesh Kumar K.V
2015-09-23 13:56   ` Anshuman Khandual
2015-09-28  4:58     ` Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 25/31] powerpc/mm: Convert 4k insert from asm " Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 26/31] powerpc/mm: Remove the dependency on pte bit position in asm code Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 27/31] powerpc/mm: Add helper for converting pte bit to hpte bits Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 28/31] powerpc/mm: Move WIMG update to helper Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 29/31] powerpc/mm: Move hugetlb related headers Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 30/31] powerpc/mm: Move THP headers around Aneesh Kumar K.V
2015-09-21  6:40 ` [PATCH 31/31] powerpc/mm: Add a _PAGE_PTE bit Aneesh Kumar K.V
2015-09-21 21:48 ` [PATCH 00/31] powerpc/mm: Update page table format for book3s 64 Scott Wood
2015-09-22  6:48   ` Aneesh Kumar K.V
2015-09-22  6:57     ` Scott Wood
2015-09-28  4:56       ` Aneesh Kumar K.V
2015-09-28 16:41         ` Scott Wood
2015-09-30  1:44           ` Michael Ellerman
2015-09-29  0:12         ` Benjamin Herrenschmidt

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