Re: [PATCH v1 00/14] Transparent Contiguous PTEs for User Mappings

From: Ryan Roberts <ryan.roberts@arm.com>
To: Barry Song <21cnbao@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
	Marc Zyngier <maz@kernel.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	Alexander Potapenko <glider@google.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Matthew Wilcox <willy@infradead.org>, Yu Zhao <yuzhao@google.com>,
	Mark Rutland <mark.rutland@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v1 00/14] Transparent Contiguous PTEs for User Mappings
Date: Mon, 10 Jul 2023 14:28:15 +0100	[thread overview]
Message-ID: <4dc1d2e1-d5d7-2812-aa8b-f8ba6b9fb207@arm.com> (raw)
In-Reply-To: <CAGsJ_4x4b5Qe2RNTHyR2MQqSkRxcuchrUgrap9WTaDtuMUttcA@mail.gmail.com>

On 10/07/2023 13:05, Barry Song wrote:
> On Thu, Jun 22, 2023 at 11:00 PM Ryan Roberts <ryan.roberts@arm.com> wrote:
>>
>> Hi All,
>>
[...]
>>
>> Performance
>> -----------
>>
>> Below results show 2 benchmarks; kernel compilation and speedometer 2.0 (a
>> javascript benchmark running in Chromium). Both cases are running on Ampere
>> Altra with 1 NUMA node enabled, Ubuntu 22.04 and XFS filesystem. Each benchmark
>> is repeated 15 times over 5 reboots and averaged.
>>
>> All improvements are relative to baseline-4k. anonfolio and exefolio are as
>> described above. contpte is this series. (Note that exefolio only gives an
>> improvement because contpte is already in place).
>>
>> Kernel Compilation (smaller is better):
>>
>> | kernel       |   real-time |   kern-time |   user-time |
>> |:-------------|------------:|------------:|------------:|
>> | baseline-4k  |        0.0% |        0.0% |        0.0% |
>> | anonfolio    |       -5.4% |      -46.0% |       -0.3% |
>> | contpte      |       -6.8% |      -45.7% |       -2.1% |
>> | exefolio     |       -8.4% |      -46.4% |       -3.7% |
> 
> sorry i am a bit confused. in exefolio case, is anonfolio included?
> or it only has large cont-pte folios on exe code? in the other words,
> Does the 8.4% improvement come from iTLB miss reduction only,
> or from both dTLB and iTLB miss reduction?

The anonfolio -> contpte -> exefolio results are incremental. So:

anonfolio: baseline-4k + anonfolio changes
contpte: anonfolio + contpte changes
exefolio: contpte + exefolio changes

So yes, exefolio includes anonfolio. Sorry for the confusion.

> 
>> | baseline-16k |       -8.7% |      -49.2% |       -3.7% |
>> | baseline-64k |      -10.5% |      -66.0% |       -3.5% |
>>
>> Speedometer 2.0 (bigger is better):
>>
>> | kernel       |   runs_per_min |
>> |:-------------|---------------:|
>> | baseline-4k  |           0.0% |
>> | anonfolio    |           1.2% |
>> | contpte      |           3.1% |
>> | exefolio     |           4.2% |
> 
> same question as above.

same answer as above.

Thanks,
Ryan

> 
>> | baseline-16k |           5.3% |
>>