From: Matthew Wilcox <willy@infradead.org>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Collingbourne <pcc@google.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Evgenii Stepanov <eugenis@google.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-mm@kvack.org, kernel test robot <lkp@intel.com>,
Linux API <linux-api@vger.kernel.org>,
linux-doc@vger.kernel.org
Subject: Re: [PATCH v3] mm: introduce reference pages
Date: Tue, 18 Aug 2020 04:00:21 +0100 [thread overview]
Message-ID: <20200818030021.GM17456@casper.infradead.org> (raw)
In-Reply-To: <c2f7efa7-0b52-b92f-79bc-a0cc26b0d92c@nvidia.com>
On Mon, Aug 17, 2020 at 07:31:39PM -0700, John Hubbard wrote:
> > Real time (s) Max RSS (KiB)
> > anon 2.237081 107088
> > memset 2.252241 112180
> > refpage 2.243786 107128
> >
> > We can see that RSS for refpage is almost the same as anon, and real
> > time overhead is 44% that of memset.
> >
>
> Are some of the numbers stale, maybe? Try as I might, I cannot combine
> anything above to come up with 44%. :)
You're not trying hard enough ;-)
(2.252241 - 2.237081) / 2.237081 = .00677668801442594166
(2.243786 - 2.237081) / 2.237081 = .00299720930981041812
.00299720930981041812 / .00677668801442594166 = .44228232189973614648
tadaa!
As I said last time this was posted, I'm just not excited by this. We go
from having a 0.68% time overhead down to an 0.30% overhead, which just
doesn't move the needle for me. Maybe there's a better benchmark than
this to show benefits from this patchset.
next prev parent reply other threads:[~2020-08-18 3:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-14 21:33 Peter Collingbourne
2020-08-18 2:31 ` John Hubbard
2020-08-18 3:00 ` Matthew Wilcox [this message]
2020-08-18 18:25 ` John Hubbard
2021-06-19 9:20 ` Peter Collingbourne
2021-06-19 9:21 ` Peter Collingbourne
2020-08-18 3:42 ` Jann Horn
2021-06-19 9:21 ` Peter Collingbourne
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