From: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>
To: "Morten Brørup" <mb@smartsharesystems.com>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: RE: [RFC] Define well known packet burst sizes
Date: Sat, 12 Oct 2024 13:55:02 +0000 [thread overview]
Message-ID: <PH0PR18MB40860DBF395CC711CF26B3A1DE7A2@PH0PR18MB4086.namprd18.prod.outlook.com> (raw)
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35E9F7CA@smartserver.smartshare.dk>
> We should define some "well known" packet burst sizes in rte_config.h.
>
A while back we had the same idea, except that it should be platform specific
Ex., for CNXK optimal burst size across workloads is 64.
Instead of rte_config.h maybe we should have it as a meson option in
meson_options.txt with default as 32.
That way platforms can also modify it in config/<arch>/meson.build
> Especially the default packet burst size is interesting;
> if known at compile time, various drivers and libraries can optimize for it (i.e.
> special handling for nb_pkts == RTE_PKT_BURST_DEFAULT).
>
> It should also be used in DPDK examples and apps, instead of defining
> MAX_PKT_BURST in each and everyone.
>
>
> Specifically:
>
> /**
> * Default packet burst size.
> *
> * Also intended for optimizing packet processing (e.g. by loop unrolling).
> */
> #define RTE_PKT_BURST_DEFAULT 32
>
> /**
> * Largest packet burst size guaranteed to be supported throughout DPDK.
> *
> * Also intended for sizing large temporary arrays of mbufs, e.g. in
> rte_pktmbuf_free_bulk().
> */
> #define RTE_PKT_BURST_MAX 512
> #define RTE_MEMPOOL_CACHE_MAX_SIZE RTE_PKT_BURST_MAX
>
> /**
> * Smallest packet burst size recommended for latency sensitive applications,
> when throughput still matters.
> *
> * Also intended for sizing small staging arrays of mbufs, e.g. in drivers.
> *
> * Note: Corresponds to one CPU cache line of object pointers.
> * - 8 on most 64 bit architectures, 16 on POWER architecture (ppc_64).
> * - 16 on all 32 bit architectures.
> */
> #define RTE_PKT_BURST_SMALL (RTE_CACHE_LINE_SIZE / sizeof(void *))
next prev parent reply other threads:[~2024-10-12 13:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-12 12:35 Morten Brørup
2024-10-12 13:55 ` Pavan Nikhilesh Bhagavatula [this message]
2024-10-12 15:07 ` Morten Brørup
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