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From: Mike Shang <mshang5@gmail.com>
Date: Fri, 7 Jul 2017 10:44:34 +0800
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Subject: [dpdk-users] Performance gain from switching to vector PMD
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Hi,
I tried to enable vector i40e for an existing dpdk application just found
that no performance gain is resulted. Is there anything we have to tune
when using vPMD ? I have gone through the dpdk document but found nothing
relevant. Any suggestions ? Or the benefits of vPMD are just not that
significant ?

ps.
I'm using 17.05 on Intel sandy bridge CPU. I have set RET_MACHINE to snb
for enabling SSE needed for vPMD. Also the preconditions required for using
I40E vPMD are missing in the document for I40E but are there in the IXGBE
sections. rx_free_thresh is at 32 to fulfill the precondition and I'm sure
vector is enablen from checking the log, that rx_vec_allowed and
rx_bulk_alloc_allowed are both true.

Thanks.