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From: Joerg Roedel <jroedel@suse.de>
To: Shaohua Li <shli@fb.com>
Cc: linux-kernel@vger.kernel.org, gang.wei@intel.com,
	hpa@linux.intel.com, mingo@kernel.org, kernel-team@fb.com,
	ning.sun@intel.com, srihan@fb.com, alex.eydelberg@intel.com
Subject: Re: [RFC] x86/tboot: add an option to disable iommu force on
Date: Wed, 22 Mar 2017 11:49:00 +0100	[thread overview]
Message-ID: <20170322104900.GE8329@suse.de> (raw)
In-Reply-To: <b93d9e540a7f0e34fbf622602c433a583130ec88.1490120859.git.shli@fb.com>

Hi Shaohua,

On Tue, Mar 21, 2017 at 11:37:51AM -0700, Shaohua Li wrote:
> IOMMU harms performance signficantly when we run very fast networking
> workloads. This is a limitation in hardware based on our observation, so
> we'd like to disable the IOMMU force on, but we do want to use TBOOT and
> we can sacrifice the DMA security bought by IOMMU. I must admit I know
> nothing about TBOOT, but TBOOT guys (cc-ed) think not eabling IOMMU is
> totally ok.

Can you elaborate a bit more on the setup where the IOMMU still harms
network performance? With the recent scalability improvements I measured
only a minimal impact on 10GBit networking.



	Joerg

  reply	other threads:[~2017-03-22 11:23 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-21 18:37 [RFC] x86/tboot: add an option to disable iommu force on Shaohua Li
2017-03-22 10:49 ` Joerg Roedel [this message]
2017-03-22 11:50   ` Shaohua Li
2017-04-03 19:19     ` Shaohua Li
2017-04-07 10:08       ` Joerg Roedel
2017-04-07 21:49         ` Sun, Ning
2017-04-10  4:31           ` Shaohua Li
2017-04-10 21:28             ` Sun, Ning
2017-04-24 16:50               ` Shaohua Li
2017-04-25 11:02                 ` Joerg Roedel

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