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From: "Morten Brørup" <mb@smartsharesystems.com>
To: "Stephen Hemminger" <stephen@networkplumber.org>
Cc: <dev@dpdk.org>, <andrew.rybchenko@oktetlabs.ru>
Subject: RE: [RFC] mbuf: performance optimization
Date: Sun, 21 Jan 2024 18:19:04 +0100	[thread overview]
Message-ID: <98CBD80474FA8B44BF855DF32C47DC35E9F180@smartserver.smartshare.dk> (raw)
In-Reply-To: <20240121090732.3cf8c5d6@hermes.local>

> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> Sent: Sunday, 21 January 2024 18.08
> 
> On Sun, 21 Jan 2024 06:32:42 +0100
> Morten Brørup <mb@smartsharesystems.com> wrote:
> 
> > I suppose that reducing mbuf->nb_segs from 16 to 8 bit is realistic,
> considering that a maximum size IP packet (64 KB) is unlikely to use
> more than 64 plus some segments. Does anyone know of any use case with
> more than 255 segments in an mbuf?
> 
> There is the case of Linux internally using super large IPv6 (and now
> IPv4) frames.
> See RFC 2675 IPv6 jumbograms
> 
> https://netdevconf.info/0x15/slides/35/BIG%20TCP.pdf

Just took at brief look at it... I suppose something similar could grow into DPDK, so we are probably better prepared by leaving nb_segs at 16 bit.

Then the proposed optimization falls to the ground. :-(

Thanks for valuable feedback, Stephen. :-)


  reply	other threads:[~2024-01-21 17:19 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-21  5:32 Morten Brørup
2024-01-21 17:07 ` Stephen Hemminger
2024-01-21 17:19   ` Morten Brørup [this message]
2024-01-22 14:27 ` [PATCH v2] mempool: test performance with larger bursts Morten Brørup
2024-01-22 14:39   ` Morten Brørup

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