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Subject: 32 bit arch optimization suggestion
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Date: Fri, 25 Aug 2023 11:40:32 +0200
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Thread-Topic: 32 bit arch optimization suggestion
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From: =?iso-8859-1?Q?Morten_Br=F8rup?= <mb@smartsharesystems.com>
To: <dev@dpdk.org>, "Ruifeng Wang" <ruifeng.wang@arm.com>,
 <bruce.richardson@intel.com>, <konstantin.v.ananyev@yandex.ru>
Cc: <olivier.matz@6wind.com>
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I was wondering...

How widely is DPDK used with 32 bit architectures?

Both phys_addr_t and rte_iova_t are cast as uint64_t in rte_common.h. =
Should they be uint32_t on 32 bit arch?

If so, the rte_mbuf structure has 12 unused byte in the first cache line =
on 32 bit arch.

Now, moving the "next" (4 byte pointer) and "tx_offload" (8 byte flags) =
fields to the first cache line could improve performance significantly, =
because this modification would leave the second cache line unused in =
most cases.


Med venlig hilsen / Kind regards,
-Morten Br=F8rup