From: Nikita Yushchenko <nikita.yushchenko@virtuozzo.com>
To: Dave Hansen <dave.hansen@intel.com>,
Will Deacon <will@kernel.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Nick Piggin <npiggin@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
"David S. Miller" <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Arnd Bergmann <arnd@arndb.de>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
sparclinux@vger.kernel.org, kernel@openvz.org
Subject: Re: [PATCH/RFC] mm: add and use batched version of __tlb_remove_table()
Date: Thu, 23 Dec 2021 12:55:38 +0300 [thread overview]
Message-ID: <22a7534c-4759-4e7e-de07-d33a3682c156@virtuozzo.com> (raw)
In-Reply-To: <290cfe1c-564f-9779-0757-5ca281055e77@intel.com>
[-- Attachment #1: Type: text/plain, Size: 1217 bytes --]
>> I currently don't have numbers for this patch taken alone. This patch
>> originates from work done some years ago to reduce cost of memory
>> accounting, and x86-only version of this patch was in virtuozzo/openvz
>> kernel since then. Other patches from that work have been upstreamed,
>> but this one was missed.
>>
>> Still it's obvious that release_pages() shall be faster that a loop
>> calling put_page() - isn't that exactly the reason why release_pages()
>> exists and is different from a loop calling put_page()?
>
> Yep, but this patch does a bunch of stuff to some really hot paths. It
> would be greatly appreciated if you could put in the effort to actually
> put some numbers behind this. Plenty of weird stuff happens on
> computers that we suck at predicting.
I found the original report about high cost of memory accounting, and tried to repeat the test described
there, with and without the patch.
The test is - run a script in 30 openvz containers in parallel, and measure average time per execution.
Script is attached.
I'm getting measurable improvement in average msecs per execution: 15360 ms without patch, 15170 ms with
patch. And this difference is reliably reproducible.
Nikita
[-- Attachment #2: calcprimes.sh --]
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next prev parent reply other threads:[~2021-12-23 9:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-17 8:19 [PATCH/RFC] mm: add and use batched version of __tlb_remove_table() Nikita Yushchenko
2021-12-17 18:26 ` Dave Hansen
2021-12-18 14:31 ` Nikita Yushchenko
2021-12-19 1:34 ` Dave Hansen
2021-12-23 9:55 ` Nikita Yushchenko [this message]
2021-12-18 0:37 ` Peter Zijlstra
2021-12-18 13:35 ` Nikita Yushchenko
[not found] ` <YbzZaFY+ht+bUtcz@ravnborg.org>
2021-12-18 13:38 ` Nikita Yushchenko
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