From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas@monjalon.net>
Subject: Re: [dpdk-stable] AVX512 bug on SkyLake
Date: Sat, 10 Nov 2018 03:13:29 +0100
Message-ID: <15598804.PupyfcORSR@xps>
References: <20181023212318.43082-1-yskoh@mellanox.com>
 <432F92CE-5714-45DC-B72F-CD8771DAFC89@intel.com> <1612642.At0RDolh7h@xps>
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Cc: stable@dpdk.org, keith.wiles@intel.com, Yongseok Koh <yskoh@mellanox.com>,
 dev@dpdk.org, Shahaf Shuler <shahafs@mellanox.com>, anatoly.burakov@intel.com,
 justin.parus@microsoft.com, christian.ehrhardt@canonical.com,
 david.coronel@canonical.com, josh.powers@canonical.com,
 jay.vosburgh@canonical.com, dan.streetman@canonical.com
To: ferruh.yigit@intel.com, bruce.richardson@intel.com,
 konstantin.ananyev@intel.com
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Below is my conclusion for this bug.
An expert of x86 is required to follow-up.

Summary:
	- CPU: Intel Skylake
	- Linux environment: Ubuntu 18.04
	- Compiler: GCC 7 or 8
	- Scenario: testpmd crashes when it starts forwarding
	- Behaviour: AVX2 version of rte_memcpy() fails if optimized for AVX512
	- Context: inline rte_memcpy() is called from
			inline rte_mempool_put_bulk(), called from
			mlx5_tx_complete() (inline or not)
	- Analysis: AVX512 optimization changes vmovdqu to vmovdqu8

Latest status can be found in Bugzilla:
	https://bugs.dpdk.org/show_bug.cgi?id=97#c35