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From: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
To: David Gibson <david@gibson.dropbear.id.au>,
	Elena Afanasova <eafanasova@gmail.com>
Cc: qemu-trivial@nongnu.org, jasowang@redhat.com,
	qemu-ppc@nongnu.org, qemu-devel@nongnu.org
Subject: Re: [PATCH] hw/net: move allocation to the heap due to very large stack frame
Date: Mon, 12 Oct 2020 13:48:37 +0200	[thread overview]
Message-ID: <ce1e6d92-1eb9-847b-8b3f-e29a23b36639@amsat.org> (raw)
In-Reply-To: <a329006c-ed11-2f1b-5766-7480c19c0462@amsat.org>

On 10/12/20 1:09 PM, Philippe Mathieu-Daudé wrote:
> On 10/10/20 8:07 AM, David Gibson wrote:
>> On Fri, Oct 09, 2020 at 07:02:56AM -0700, Elena Afanasova wrote:
>>> >From 09905773a00e417d3a37c12350d9e55466fdce8a Mon Sep 17 00:00:00 2001
>>> From: Elena Afanasova <eafanasova@gmail.com>
>>> Date: Fri, 9 Oct 2020 06:41:36 -0700
>>> Subject: [PATCH] hw/net: move allocation to the heap due to very 
>>> large stack
>>>   frame
>>
>> Patch looks fine, but some more details of the motivation would be
>> nice.  I wouldn't have thought that the size of a network packet
>> counted as a "very large" stack frame by userspace standards.
> 
> Maybe academia doing research on "super jumbo frames"?
> 
> "Super jumbo frames ... increase the path MTU of high-performance
> national research and education networks from 1500 bytes to 9000
> bytes or so, a subsequent increase, possibly to 64,000 bytes"
> 
> (https://en.wikipedia.org/wiki/Jumbo_frame#Super_jumbo_frames)

The one I was actually looking for is the IPv6 jumbogram:

"An optional feature of IPv6, the jumbo payload option, allows the 
exchange of packets with payloads of up to one byte less than 4 GiB,
by making use of a 32-bit length field."

(https://en.wikipedia.org/wiki/Jumbogram)


      reply	other threads:[~2020-10-12 12:08 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-09 14:02 [PATCH] hw/net: move allocation to the heap due to very large stack frame Elena Afanasova
2020-10-09 14:14 ` Richard Henderson
2020-10-09 14:25 ` Philippe Mathieu-Daudé
2020-10-09 14:48 ` Greg Kurz
2020-10-09 14:55 ` Li Qiang
2020-10-10  6:07 ` David Gibson
2020-10-10 15:53   ` Elena Afanasova
2020-10-12  5:30     ` David Gibson
2020-10-12 10:44       ` Thomas Huth
2020-10-12 13:45         ` Paolo Bonzini
2020-10-13  5:32           ` David Gibson
2020-10-14 14:15             ` Elena Afanasova
2020-10-16  0:32               ` David Gibson
2020-10-11  2:23   ` Li Qiang
2020-10-12  5:28     ` David Gibson
2020-10-12 11:09   ` Philippe Mathieu-Daudé
2020-10-12 11:48     ` Philippe Mathieu-Daudé [this message]

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