netdev - RE: [v1 0/6] *** nps

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <DB4PR02MB2725A45B664C42E3AB7B98ED6780@DB4PR02MB272.eurprd02.prod.outlook.com>
Date:	Tue, 18 Aug 2015 05:04:20 +0000
From:	Noam Camus <noamc@...hip.com>
To:	David Miller <davem@...emloft.net>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"Alexey.Brodkin@...opsys.com" <Alexey.Brodkin@...opsys.com>,
	"vgupta@...opsys.com" <vgupta@...opsys.com>,
	Tal Zilcer <talz@...hip.com>
Subject: RE: [v1 0/6] *** nps_enet fixups ***

From: David Miller [mailto:davem@...emloft.net] 
Sent: Monday, August 17, 2015 8:36 PM


> You should not move TX completion out of NAPI handling, NAPI poll is exactly where it belongs.
>
> If you handle it in hardware interrupt context you have to use
> dev_kfree_skb_irq() which defers the operation to software interrupt context anyways and is thus expensive.

> Whereas if you keep TX completion in your NAPI handler the kfree is handled synchronously and efficiently, as well as making SKB's potentially available for RX reclaim.

I followed "Hardware Architecture" section from:
http://www.linuxfoundation.org/collaborate/workgroups/networking/napi
and came up with "reduce processing latency" idea.

Anyway, I will restore TX completion back to NAPI poll.

> I'm not applying this series, you are doing with TX handling exactly what we tell people not to do.

I will come up with revised series in v2.

Noam
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html