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  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]
Date:	Sat, 15 Sep 2012 14:09:09 +0200
From:	Joakim Tjernlund <>
To:	Stephen Hemminger <>
Subject: Re: interrupt coalescing and CSUM offload

Stephen Hemminger <> wrote on 2012/09/14 18:32:52:
> On Fri, 14 Sep 2012 16:35:13 +0200
> Joakim Tjernlund <> wrote:
> >
> > I am adding interrupt coalescing to the ucc_geth driver. Unfortunately
> > there is only support for RX interrupt coalescing.
> > I wonder if there is any way "simulate" TX interrupt coalescing?
> >
> > I am also looking at adding HWCSUM support but this device can only do
> > IP header CSUM offload. This doesn't seem to be an option in Linux?
> > As I understand it, one must do CSUM offload for the whole frame, both
> > IP header and TCP/UDP csums?
> >
> >  Jocke
> There are a few drivers that turn off TX interrupt completely.
> They cleanup TX buffers on next send and have a timer to cleanup

Only on send? Currently ucc_geth does TX free in napi(where RX is processed too).
It would be nice if one could indicate to the drivers xmit() if there
are more frames to be sent. Then xmit() could choose not to turn on TX irq for
preceding frames.

> as well. This has performance benefits, but it does cause issues
> with local flow control (the freeing of skb is used to rate
> limit local traffic).

Was my reasoning correct w.r.t CSUM?

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists