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From: "Tobias Fiebig" <tobias@fiebig.nl>
To: "'Stefan Hajnoczi'" <stefanha@redhat.com>, <qemu-devel@nongnu.org>
Cc: <jasowang@redhat.com>, <qemu-stable@nongnu.org>,
	"'Russell King - ARM Linux'" <linux@armlinux.org.uk>
Subject: RE: [PATCH for-7.2] rtl8139: honor large send MSS value
Date: Wed, 16 Nov 2022 03:58:54 +0100	[thread overview]
Message-ID: <011801d8f967$5dad0f00$19072d00$@fiebig.nl> (raw)
In-Reply-To: 

Heho,
I just tested around with the patch;
Good news: Certainly my builds are being executed. Also, if I patch the old code to have a MAX_MTU <= the max MTU on my path, throughput is ok.

Bad news: Something is wrong with getting the MSS in the patch you shared. When enabling DPRINT, values are off (sent MSS vs. printed MSS):
600 2060
800 2308
1000 2316
1023 2307
1200 3076
1400 3340 (most likely clamped to 1320)

Fiddling around a bit more, I found txdw0 printed earlier in the stack as hex (sent MSS, txdw0):
769 900502f5
1000 900503dc
1280 900504f4
1281 900504f5
1301 90050509
1317 90050519
1320 9005051c

This maps rather well to:
MSS = txdw0 - 2416246772 
MSS = txdw0 - 9004FFF4

Sadly, my C is 'non-existent' and it is kind-of 4AM, so also not in the brainspace to fill those gaps. But if one of you could look at the patch again, that would be nice. Otherwise, I should have some brainspace for this tomorrow night (UTC) again.

With best regards,
Tobias



  parent reply	other threads:[~2022-11-16  3:00 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-15 16:36 [PATCH for-7.2] rtl8139: honor large send MSS value Stefan Hajnoczi
2022-11-15 23:36 ` Tobias Fiebig
2022-11-16  4:19   ` Jason Wang
2022-11-16  2:58 ` Tobias Fiebig [this message]
2022-11-16  6:54   ` Jason Wang
2022-11-16 10:04     ` Tobias Fiebig
2022-11-16 11:20     ` Tobias Fiebig
2022-11-16 15:47       ` Stefan Hajnoczi
2022-11-17  2:49         ` Tobias Fiebig
2022-11-17 11:07           ` Stefan Hajnoczi
2022-11-17 11:15             ` Stefan Hajnoczi
2022-11-17 11:26               ` Tobias Fiebig
2022-11-17 16:56                 ` Stefan Hajnoczi
2022-11-17 17:02                   ` Tobias Fiebig
2022-11-17 20:42                   ` Tobias Fiebig
2022-11-17 22:51                     ` Stefan Hajnoczi
2022-11-18  7:10                 ` Jason Wang
2022-11-16  4:13 ` Jason Wang

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