From: Eugeniu Rosca <erosca@de.adit-jv.com>
To: Jia He <hejianet@gmail.com>, Will Deacon <will.deacon@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>,
Wei Yang <richard.weiyang@gmail.com>,
Kees Cook <keescook@chromium.org>,
Laura Abbott <labbott@redhat.com>,
Vladimir Murzin <vladimir.murzin@arm.com>,
Philip Derrin <philip@cog.systems>,
AKASHI Takahiro <takahiro.akashi@linaro.org>,
James Morse <james.morse@arm.com>,
Steve Capper <steve.capper@arm.com>,
Gioh Kim <gi-oh.kim@profitbricks.com>,
Vlastimil Babka <vbabka@suse.cz>, Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>,
Kemi Wang <kemi.wang@intel.com>, Petr Tesarik <ptesarik@suse.com>,
YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Nikolay Borisov <nborisov@suse.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
Daniel Vacek <neelx@redhat.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>, Jia He <jia.he@hxt-semitech.com>,
"George G. Davis" <george_davis@mentor.com>,
Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>,
Andy Lowe <andy_lowe@mentor.com>,
<linux-renesas-soc@vger.kernel.org>,
Eugeniu Rosca <roscaeugeniu@gmail.com>,
Eugeniu Rosca <erosca@de.adit-jv.com>
Subject: Re: [PATCH v11 0/3] remain and optimize memblock_next_valid_pfn on arm and arm64
Date: Fri, 14 Sep 2018 20:50:51 +0200 [thread overview]
Message-ID: <20180914185051.GA22530@vmlxhi-102.adit-jv.com> (raw)
In-Reply-To: <20180907144447.GD12788@arm.com>
+ Renesas people
Hello Will, hello Ard,
On Fri, Sep 07, 2018 at 03:44:47PM +0100, Will Deacon wrote:
> On Thu, Sep 06, 2018 at 01:24:22PM +0200, Ard Biesheuvel wrote:
> > OK so we can summarize the benefits of this series as follows:
> > - boot time on a virtual model of a Samurai CPU drops from 109 to 62 seconds
> > - boot time on a QDF2400 arm64 server with 96 GB of RAM drops by ~15
> > *milliseconds*
> >
> > Google was not very helpful in figuring out what a Samurai CPU is and
> > why we should care about the boot time of Linux running on a virtual
> > model of it, and the 15 ms speedup is not that compelling either.
> >
> > Apologies to Jia that it took 11 revisions to reach this conclusion,
> > but in /my/ opinion, tweaking the fragile memblock/pfn handling code
> > for this reason is totally unjustified, and we're better off
> > disregarding these patches.
>
> Oh, we're talking about a *simulator* for the significant boot time
> improvement here? I didn't realise that, so I agree that the premise of
> this patch set looks pretty questionable given how much "fun" we've had
> with the memmap on arm and arm64.
>
> Will
Similar to https://lkml.org/lkml/2018/1/24/420, my measurements show that
the boot time of R-Car H3-ES2.0 Salvator-X (having 4GiB RAM) is decreased
by ~135-140ms with this patch-set applied on top of v4.19-rc3.
I agree that in the Desktop realm you would barely perceive the 140ms
difference, but saving 140ms on the automotive SoC (designed for products
which must comply with 2s-to-rear-view-camera NHTSA US regulations) *is*
significant.
FWIW, cppcheck and `checkpatch --strict` report style issues for
patches #2 and #3. I hope these can be fixed and the review process
can go on? From functional standpoint, I did some dynamic testing on
H3-Salvator-X with UBSAN/KASAN=y and didn't observe any regressions, so:
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Best regards,
Eugeniu.
next prev parent reply other threads:[~2018-09-14 18:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-22 3:07 Jia He
2018-08-22 3:07 ` [PATCH v11 1/3] arm: arm64: introduce CONFIG_HAVE_MEMBLOCK_PFN_VALID Jia He
2018-08-22 3:07 ` [PATCH v11 2/3] mm: page_alloc: remain memblock_next_valid_pfn() on arm/arm64 Jia He
2018-08-22 3:07 ` [PATCH v11 3/3] mm: page_alloc: reduce unnecessary binary search in memblock_next_valid_pfn Jia He
2018-09-05 21:57 ` [PATCH v11 0/3] remain and optimize memblock_next_valid_pfn on arm and arm64 Andrew Morton
2018-09-06 10:47 ` Will Deacon
2018-09-06 11:24 ` Ard Biesheuvel
2018-09-07 14:44 ` Will Deacon
2018-09-14 18:50 ` Eugeniu Rosca [this message]
2019-06-08 4:22 ` Hanjun Guo
2019-06-10 13:16 ` Ard Biesheuvel
2019-06-11 15:18 ` Hanjun Guo
2019-06-12 1:05 ` Jia He
2019-06-12 12:48 ` Hanjun Guo
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