netdev - Re: [net-next 11/13] igb: Make Tx budget for NAPI user adjustable

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 for Android: free password hash cracker in your pocket

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

Message-Id: <20110919.170033.344802441047363137.davem@davemloft.net>
Date:	Mon, 19 Sep 2011 17:00:33 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	alexander.h.duyck@...el.com
Cc:	bhutchings@...arflare.com, jeffrey.t.kirsher@...el.com,
	netdev@...r.kernel.org, gospo@...hat.com
Subject: Re: [net-next 11/13] igb: Make Tx budget for NAPI user adjustable

From: Alexander Duyck <alexander.h.duyck@...el.com>
Date: Mon, 19 Sep 2011 09:32:18 -0700

> The fact is ixgbe has been using this parameter this way for over 2
> years now and the main goal of this patch was just to synchronize how
> things work on igb and ixgbe.
> 
> Our hardware doesn't have a mechanism for firing an interrupt after X
> number of frames so instead we simply have modified things so that we
> will only process X number of frames and then fire another
> interrupt/poll if needed.  As such we aren't that far out of
> compliance with the meaning of how this parameter is supposed to be
> used.

All I can say is this was a huge mistake you therefore need to revert
the IXGBE change, these ethtool settings are not for changing NAPI or
software interrupt behavior.

And if you guys plan to be difficult on this and refuse to remove the
IXGBE bits, I'm letting you guys know ahead of time that I'll do it
for you.

If the hardware can't support this facility, neither should these
ethtool hooks, because the whole point is to avoid hardware interrupts
from firing using these parameters.

Propose new mechanisms to control NAPI behavior if you want.
--
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