From: Joerg Roedel <jroedel@suse.de>
To: Shaohua Li <shli@fb.com>
Cc: Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org, gang.wei@intel.com,
hpa@linux.intel.com, kernel-team@fb.com, ning.sun@intel.com,
srihan@fb.com, alex.eydelberg@intel.com
Subject: Re: [PATCH V2] x86/tboot: add an option to disable iommu force on
Date: Thu, 27 Apr 2017 17:18:55 +0200 [thread overview]
Message-ID: <20170427151855.GW5077@suse.de> (raw)
In-Reply-To: <20170427144901.GA98840@dhcp-172-26-110-153.dhcp.thefacebook.com>
On Thu, Apr 27, 2017 at 07:49:02AM -0700, Shaohua Li wrote:
> This is exactly the usage for us. And please note, not everybody should
> sacrifice the DMA security. It is only required when the pcie device hits iommu
> hardware limitation. In our enviroment, normal network workloads (as high as
> 60k pps) are completely ok with iommu enabled. Only the XDP workload, which can
> do around 200k pps, is suffering from the problem. So completely forcing iommu
> off for some workloads without the performance issue isn't good because of the
> DMA security.
How big are the packets in your XDP workload? I also run pps tests for
performance measurement on older desktop-class hardware
(Xeon E5-1620 v2 and AMD FX 6100) and 10GBit network
hardware, and easily get over the 200k pps mark with IOMMU enabled. The
Intel system can receive >900k pps and the AMD system is still at
~240k pps.
But my tests only send IPv4/UDP packets with 8bytes of payload, so that
is probably different to your setup.
Joerg
next prev parent reply other threads:[~2017-04-27 15:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-26 16:18 [PATCH V2] x86/tboot: add an option to disable iommu force on Shaohua Li
2017-04-26 21:59 ` Joerg Roedel
2017-04-27 6:52 ` Ingo Molnar
2017-04-28 22:07 ` Joerg Roedel
2017-04-27 6:51 ` Ingo Molnar
2017-04-27 8:42 ` Joerg Roedel
2017-04-27 14:49 ` Shaohua Li
2017-04-27 15:18 ` Joerg Roedel [this message]
2017-04-27 15:41 ` Shaohua Li
2017-04-27 16:04 ` Joerg Roedel
2017-05-05 6:59 ` Ingo Molnar
2017-05-05 8:40 ` Joerg Roedel
2017-05-06 9:48 ` Ingo Molnar
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