netdev - stmmac mitigation and ethtool coalesce parameters

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>] [day] [month] [year] [list]

Date:	Wed, 22 Aug 2012 09:14:00 +0200
From:	Giuseppe CAVALLARO <peppe.cavallaro@...com>
To:	ML netdev <netdev@...r.kernel.org>
Subject: stmmac mitigation and ethtool coalesce parameters

Hello
I'm reworking the mitigation schema in the stmmac and removing the old
and dead STMMAC_TIMER code.

On new chips we have an HW RX-Watchdog that can be used for mitigating
the Rx-interrupts and first results look promising.

Before posting the patches I have a doubt about the ethtool coalesce
parameters to use in the driver to tune the following parameters:

- On Rx-side I have:
  a parameter that is the RI Watchdog Timer count. It indicates the
  number of system clock cycles.

- On Tx-side, the mitigation schema I'm using is based on a SW timer
  that calls the tx function (stmmac_tx) to reclaim the resource after
  transmitting the frames.
  Also there is another parameter (like a threshold) used to program
  the descriptors avoiding to set the interrupt on completion bit in
  when the frame is sent (xmit). This means that the stmmac_tx can be
  called by the ISR too.   This approach is showing really good figures
  as well.

so I wonder which are the appropriate ethtool coalesce parameters to
use? Or could I tune them by using sysfs entries?

Welcome advice.

Peppe
--
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