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From: "Morten Brørup" <mb@smartsharesystems.com>
To: "David Christensen" <drc@linux.vnet.ibm.com>, <dev@dpdk.org>,
	"Bruce Richardson" <bruce.richardson@intel.com>,
	"Konstantin Ananyev" <konstantin.v.ananyev@yandex.ru>
Cc: "Jan Viktorin" <viktorin@rehivetech.com>,
	"Ruifeng Wang" <ruifeng.wang@arm.com>,
	"Stanislaw Kardach" <kda@semihalf.com>
Subject: RE: [RFC v2] non-temporal memcpy
Date: Tue, 19 Jul 2022 20:41:27 +0200	[thread overview]
Message-ID: <98CBD80474FA8B44BF855DF32C47DC35D871D5@smartserver.smartshare.dk> (raw)
In-Reply-To: <0e4bdf5e-3cac-c8ec-786e-17e0ea16ddf0@linux.vnet.ibm.com>

> From: David Christensen [mailto:drc@linux.vnet.ibm.com]
> Sent: Tuesday, 19 July 2022 20.01
> 
> On 7/19/22 8:26 AM, Morten Brørup wrote:
> > This RFC proposes a set of functions optimized for non-temporal
> memory copy.
> >
> > At this stage, I am asking for feedback on the concept.
> >
> > Applications sometimes data to another memory location, which is only
> used
> > much later.
> > In this case, it is inefficient to pollute the data cache with the
> copied
> > data.
> >
> > An example use case (originating from a real life application):
> > Copying filtered packets, or the first part of them, into a capture
> buffer
> > for offline analysis.
> >
> > The purpose of these functions is to achieve a performance gain by
> not
> > polluting the cache when copying data.
> > Although the throughput may be improved by further optimization, I do
> not
> > consider througput optimization relevant initially.
> >
> Assume that fallback to the standard temporal memcpy is an acceptable
> implementation when not supported by the architecture, yes?

Yes, that is exactly what I envisioned.

Furthermore, stores unaligned to a degree not supported by the architecture, will also use temporal mempcy - at least for the unaligned first and last part of the copy. The middle (aligned) part may use non-temporal copy.

> My internal
> queries on the POWER side indicate that there's no support in P8/P9/P10
> ISA for such functionality.
> 
> Dave

Thank you for quick feedback, Dave!


  reply	other threads:[~2022-07-19 18:41 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-19 15:26 Morten Brørup
2022-07-19 18:00 ` David Christensen
2022-07-19 18:41   ` Morten Brørup [this message]
2022-07-19 18:51     ` Stanisław Kardach
2022-07-19 22:15       ` Morten Brørup
2022-07-21 23:19 ` Konstantin Ananyev
2022-07-22 10:44   ` Morten Brørup
2022-07-24 13:35     ` Konstantin Ananyev
2022-07-24 22:18       ` Morten Brørup
2022-07-29 10:00         ` Konstantin Ananyev
2022-07-29 10:46           ` Morten Brørup
2022-07-29 11:50             ` Konstantin Ananyev
2022-07-29 17:17               ` Morten Brørup
2022-07-29 22:00                 ` Konstantin Ananyev
2022-07-30  9:51                   ` Morten Brørup
2022-08-02  9:05                     ` Konstantin Ananyev
2022-07-29 12:13             ` Konstantin Ananyev
2022-07-29 16:05               ` Stephen Hemminger
2022-07-29 17:29                 ` Morten Brørup
2022-08-07 20:40                 ` Mattias Rönnblom
2022-08-09  9:24                   ` Morten Brørup
2022-08-09 11:53                     ` Mattias Rönnblom
2022-10-09 16:16                       ` Morten Brørup
2022-07-29 18:13               ` Morten Brørup
2022-07-29 19:49                 ` Konstantin Ananyev
2022-07-29 20:26                   ` Morten Brørup
2022-07-29 21:34                     ` Konstantin Ananyev
2022-08-07 20:20                     ` Mattias Rönnblom
2022-08-09  9:34                       ` Morten Brørup
2022-08-09 11:56                         ` Mattias Rönnblom
2022-08-10 21:05                     ` Honnappa Nagarahalli
2022-08-11 11:50                       ` Mattias Rönnblom
2022-08-11 16:26                         ` Honnappa Nagarahalli
2022-07-25  1:17       ` Honnappa Nagarahalli
2022-07-27 10:26         ` Morten Brørup
2022-07-27 17:37           ` Honnappa Nagarahalli
2022-07-27 18:49             ` Morten Brørup
2022-07-27 19:12               ` Stephen Hemminger
2022-07-28  9:00                 ` Morten Brørup
2022-07-27 19:52               ` Honnappa Nagarahalli
2022-07-27 22:02                 ` Stanisław Kardach
2022-07-28 10:51                   ` Morten Brørup
2022-07-29  9:21                     ` Konstantin Ananyev
2022-08-07 20:25 ` Mattias Rönnblom
2022-08-09  9:46   ` Morten Brørup
2022-08-09 12:05     ` Mattias Rönnblom
2022-08-09 15:00       ` Morten Brørup
2022-08-10 11:47         ` Mattias Rönnblom
2022-08-09 15:26     ` Stephen Hemminger
2022-08-09 17:24       ` Morten Brørup
2022-08-10 11:59         ` Mattias Rönnblom
2022-08-10 12:12           ` Morten Brørup
2022-08-10 11:55       ` Mattias Rönnblom
2022-08-10 12:18         ` Morten Brørup
2022-08-10 21:20           ` Honnappa Nagarahalli
2022-08-11 11:53             ` Mattias Rönnblom
2022-08-11 22:24               ` Honnappa Nagarahalli

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