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From: Konstantin Ananyev <konstantin.ananyev@huawei.com>
To: "Morten Brørup" <mb@smartsharesystems.com>,
	"Stephen Hemminger" <stephen@networkplumber.org>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	Bruce Richardson <bruce.richardson@intel.com>
Subject: RE: [PATCH] eal/x86: optimize memcpy of small 64-byte blocks
Date: Wed, 5 Aug 2026 05:45:51 +0000	[thread overview]
Message-ID: <6f474724bc22441a8a4f516f3398ca76@huawei.com> (raw)
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35F659B8@smartserver.smartshare.dk>



> > From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> > Sent: Tuesday, 4 August 2026 17.52
> >
> > On Tue,  4 Aug 2026 14:33:04 +0000
> > Morten Brørup <mb@smartsharesystems.com> wrote:
> >
> > > +	/* Common way for small copy size of 64-byte blocks. Unlikely, so
> > constant size only */
> > > +	if (__rte_constant(n) && (n & 63) == 0 && n <=
> > RTE_MEMCPY_BLOCK_64_MAX) {
> > > +		void *ret = dst;
> > > +
> >
> > Maybe just let compiler decide, it will generate vector instructions in
> > most cases.
> >
> > 	if (__rte_constant(n))
> > 		return mempcpy(dst, src, n);
> 
> Maybe in most, but not in all:
> https://godbolt.org/z/KvdKqT5rY

With '-mavx' or '-mavx512f' it looks like it does for your sample code.



  reply	other threads:[~2026-08-05  5:45 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-04 14:33 [PATCH] eal/x86: optimize memcpy of small 64-byte blocks Morten Brørup
2026-08-04 14:33 ` [RFC PATCH] pile stack and mempool driver (resend) Morten Brørup
2026-08-04 14:38   ` Morten Brørup
2026-08-04 15:52 ` [PATCH] eal/x86: optimize memcpy of small 64-byte blocks Stephen Hemminger
2026-08-04 16:25   ` Morten Brørup
2026-08-05  5:45     ` Konstantin Ananyev [this message]
2026-08-05  5:56       ` Morten Brørup
2026-08-05  6:50         ` Konstantin Ananyev
2026-08-05  8:36           ` Morten Brørup
2026-08-05 17:16             ` Konstantin Ananyev
2026-08-05 20:28               ` Morten Brørup
2026-08-06  7:58                 ` Konstantin Ananyev
2026-08-06  9:17                   ` Morten Brørup
2026-08-04 19:11 ` Morten Brørup
2026-08-04 20:42   ` Stephen Hemminger
2026-08-05 17:10 ` Konstantin Ananyev
2026-08-05 20:16   ` Morten Brørup
2026-08-06  7:43     ` Konstantin Ananyev
2026-08-06  8:00       ` Morten Brørup
2026-08-06 10:17 ` [PATCH v2] " Morten Brørup

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