From: "Morten Brørup" <mb@smartsharesystems.com>
To: "Tyler Retzlaff" <roretzla@linux.microsoft.com>
Cc: <dev@dpdk.org>, "Andrew Boyer" <andrew.boyer@amd.com>,
"Andrew Rybchenko" <andrew.rybchenko@oktetlabs.ru>,
"Bruce Richardson" <bruce.richardson@intel.com>,
"Chenbo Xia" <chenbox@nvidia.com>,
"Konstantin Ananyev" <konstantin.v.ananyev@yandex.ru>,
"Maxime Coquelin" <maxime.coquelin@redhat.com>
Subject: RE: [PATCH] mbuf: replace GCC marker extension with C11 anonymous unions
Date: Wed, 31 Jan 2024 23:39:52 +0100 [thread overview]
Message-ID: <98CBD80474FA8B44BF855DF32C47DC35E9F1D7@smartserver.smartshare.dk> (raw)
In-Reply-To: <20240131210921.GD11576@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
> From: Tyler Retzlaff [mailto:roretzla@linux.microsoft.com]
> Sent: Wednesday, 31 January 2024 22.09
>
> On Wed, Jan 31, 2024 at 10:18:37AM +0100, Morten Brørup wrote:
> > > From: Tyler Retzlaff [mailto:roretzla@linux.microsoft.com]
> > > Sent: Wednesday, 31 January 2024 00.26
> > >
[...]
> > > struct rte_mempool *pool; /**< Pool from which mbuf was
> > > allocated. */
> > >
> > > /* second cache line - fields only used in slow path or on TX */
> > > - RTE_MARKER cacheline1 __rte_cache_min_aligned;
> > > + union {
> > > + void *cacheline1;
> >
> > The __rte_cache_min_aligned cannot be removed. It provides cache line
> alignment for 32 bit platforms, where pointers in the first cache line
> only use 4 byte.
>
> oh no i forgot i needed to figure this out before submission. now that
> it's here though i could use some help / suggestions.
>
> the existing __rte_cache_min_aligned (and indeed standard alignas)
> facilities are not of great utility when applied to anonymous unions,
> further complicating things is that it also has to work with C++.
>
> i'll take this away and work on it some more but does anyone here have
> a
> suggestion on how to align this anonymous union data member to the
> desired alignment *without* the union being padded to min cache line
> size and as a consequence causing the rte_mbuf struct to be 3 instead
> of 2 cache lines? (that's essentially the problem i need help solving).
I would suggest to simply remove __rte_cache_min_aligned (and the implicit padding that comes with it), and instead conditionally (#ifdef RTE_ARCH_32) add an explicit uintptr_t padding field after each pointer field in the rte_mbuf struct's first cache line.
But that would break the 32-bit ABI, so instead insert the explicit padding in the rte_mbuf struct at the end of its first cache line (where the implicit padding from __rte_cache_min_aligned is currently added), something like this:
struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
+#ifdef RTE_ARCH_32
+ /* Padding to ensure correct alignment of cacheline1. */
+ uintptr_t pad_buf_addr;
+#if !RTE_IOVA_IN_MBUF
+ uintptr_t pad_next;
+#endif
+#endif /* RTE_ARCH_32 */
/* second cache line - fields only used in slow path or on TX */
To be on the safe side, add a static_assert to verify that offsetof(struct rte_mbuf, cacheline1) == RTE_CACHE_LINE_MIN_SIZE. This should be true for all architectures, i.e. both 64 bit and 32 bit.
next prev parent reply other threads:[~2024-01-31 22:39 UTC|newest]
Thread overview: 171+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-30 23:26 [PATCH] " Tyler Retzlaff
2024-01-30 23:26 ` [PATCH] mbuf: " Tyler Retzlaff
2024-01-31 9:18 ` Morten Brørup
2024-01-31 21:09 ` Tyler Retzlaff
2024-01-31 22:39 ` Morten Brørup [this message]
2024-01-31 13:49 ` Bruce Richardson
2024-01-31 20:45 ` Tyler Retzlaff
2024-01-31 22:55 ` Morten Brørup
2024-02-13 6:45 ` [PATCH v2] RFC: " Tyler Retzlaff
2024-02-13 6:45 ` [PATCH v2] mbuf: " Tyler Retzlaff
2024-02-13 16:58 ` Morten Brørup
2024-02-13 18:48 ` Tyler Retzlaff
2024-02-13 19:27 ` Morten Brørup
2024-02-13 20:00 ` Tyler Retzlaff
2024-02-13 8:57 ` [PATCH v2] RFC: " Bruce Richardson
2024-02-13 17:09 ` Morten Brørup
2024-02-13 23:33 ` [PATCH v3] RFC deprecate RTE_MARKER in struct rte_mbuf Tyler Retzlaff
2024-02-13 23:33 ` [PATCH v3] mbuf: deprecate GCC marker in rte mbuf struct Tyler Retzlaff
2024-02-14 10:46 ` Morten Brørup
2024-02-14 20:16 ` Tyler Retzlaff
2024-02-14 10:49 ` [PATCH v3] RFC deprecate RTE_MARKER in struct rte_mbuf Morten Brørup
2024-02-26 1:18 ` Stephen Hemminger
2024-02-15 6:21 ` [PATCH v4 00/18] stop using zero sized marker fields Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 01/18] mbuf: deprecate GCC marker in rte mbuf struct Tyler Retzlaff
2024-02-18 2:28 ` fengchengwen
2024-02-18 12:39 ` Thomas Monjalon
2024-02-18 13:07 ` Morten Brørup
2024-02-18 15:22 ` Thomas Monjalon
2024-02-18 16:20 ` Morten Brørup
2024-02-20 17:24 ` Tyler Retzlaff
2024-02-20 17:20 ` Tyler Retzlaff
2024-02-20 17:53 ` Thomas Monjalon
2024-02-20 19:16 ` Thomas Monjalon
2024-02-20 19:37 ` Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 02/18] mbuf: stop using zero sized marker fields Tyler Retzlaff
2024-02-18 2:38 ` fengchengwen
2024-02-15 6:21 ` [PATCH v4 03/18] net/i40e: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 04/18] net/iavf: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 05/18] net/ice: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 06/18] net/ixgbe: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 07/18] net/mlx5: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 08/18] net/sfc: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 09/18] net/bnxt: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 10/18] net/enic: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 11/18] net/fm10k: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 12/18] net/hns3: " Tyler Retzlaff
2024-02-18 3:00 ` fengchengwen
2024-02-15 6:21 ` [PATCH v4 13/18] net/ionic: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 14/18] net/thunderx: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 15/18] net/virtio: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 16/18] net/cnxk: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 17/18] common/idpf: " Tyler Retzlaff
2024-02-15 6:21 ` [PATCH v4 18/18] examples/dma: " Tyler Retzlaff
2024-02-15 9:37 ` [PATCH v4 00/18] " Morten Brørup
2024-02-24 8:21 ` [PATCH v5 00/22] stop using RTE_MARKER extensions Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 01/22] eal: provide macro to expand marker extensions Tyler Retzlaff
2024-02-24 10:51 ` Thomas Monjalon
2024-02-24 11:18 ` Thomas Monjalon
2024-02-24 8:21 ` [PATCH v5 02/22] mbuf: expand rte markers empty when building with MSVC Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 03/22] security: " Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 04/22] cryptodev: " Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 05/22] mbuf: stop using mbuf cacheline marker fields Tyler Retzlaff
2024-02-24 10:58 ` Thomas Monjalon
2024-02-26 18:20 ` Stephen Hemminger
2024-02-24 8:21 ` [PATCH v5 06/22] mbuf: add mbuf descriptor accessors Tyler Retzlaff
2024-02-24 11:01 ` Thomas Monjalon
2024-02-24 8:21 ` [PATCH v5 07/22] common/idpf: use " Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 08/22] net/bnxt: " Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 09/22] net/cnxk: " Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 10/22] net/enic: " Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 11/22] net/fm10k: " Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 12/22] net/hns3: " Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 13/22] net/i40e: " Tyler Retzlaff
2024-02-24 8:21 ` [PATCH v5 14/22] net/iavf: " Tyler Retzlaff
2024-02-24 8:22 ` [PATCH v5 15/22] net/ice: " Tyler Retzlaff
2024-02-24 8:22 ` [PATCH v5 16/22] net/ionic: " Tyler Retzlaff
2024-02-24 8:22 ` [PATCH v5 17/22] net/ixgbe: " Tyler Retzlaff
2024-02-24 8:22 ` [PATCH v5 18/22] net/mlx5: " Tyler Retzlaff
2024-02-24 8:22 ` [PATCH v5 19/22] net/octeon_ep: " Tyler Retzlaff
2024-02-24 8:22 ` [PATCH v5 20/22] net/sfc: " Tyler Retzlaff
2024-02-24 8:22 ` [PATCH v5 21/22] net/thunderx: " Tyler Retzlaff
2024-02-24 8:22 ` [PATCH v5 22/22] net/virtio: " Tyler Retzlaff
2024-02-24 10:42 ` [PATCH v5 00/22] stop using RTE_MARKER extensions Morten Brørup
2024-02-24 11:13 ` Thomas Monjalon
2024-02-24 11:23 ` Morten Brørup
2024-02-27 5:41 ` [PATCH v6 00/23] stop and remove RTE_MARKER typedefs Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 01/23] mbuf: add accessors for rearm and Rx descriptor fields Tyler Retzlaff
2024-02-27 9:10 ` Morten Brørup
2024-02-27 17:17 ` Tyler Retzlaff
2024-02-28 8:28 ` Morten Brørup
2024-02-28 16:20 ` Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 02/23] mbuf: consolidate driver asserts for mbuf struct Tyler Retzlaff
2024-02-27 10:02 ` Konstantin Ananyev
2024-03-14 16:51 ` Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 03/23] common/idpf: use mbuf descriptor accessors Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 04/23] net/bnxt: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 05/23] net/cnxk: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 06/23] net/enic: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 07/23] net/fm10k: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 08/23] net/hns3: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 09/23] net/i40e: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 10/23] net/iavf: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 11/23] net/ice: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 12/23] net/ionic: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 13/23] net/ixgbe: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 14/23] net/mlx5: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 15/23] net/octeon_ep: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 16/23] net/sfc: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 17/23] net/thunderx: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 18/23] net/virtio: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 19/23] examples/dma: use mbuf descriptor accessor Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 20/23] mbuf: remove and stop using rte marker fields Tyler Retzlaff
2024-02-27 9:15 ` Morten Brørup
2024-02-27 10:03 ` Konstantin Ananyev
2024-02-27 15:18 ` David Marchand
2024-02-27 16:04 ` Morten Brørup
2024-02-27 17:23 ` Tyler Retzlaff
2024-02-28 10:42 ` David Marchand
2024-02-28 14:03 ` Dodji Seketeli
2024-02-28 14:43 ` David Marchand
2024-02-29 14:50 ` Dodji Seketeli
2024-02-28 14:18 ` David Marchand
2024-02-28 15:01 ` Morten Brørup
2024-02-28 15:33 ` David Marchand
2024-02-28 17:20 ` Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 21/23] security: remove " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 22/23] cryptodev: " Tyler Retzlaff
2024-02-27 5:41 ` [PATCH v6 23/23] devtools: forbid new use of rte marker typedefs Tyler Retzlaff
2024-03-20 22:01 ` [PATCH v7 0/4] remove use of RTE_MARKER fields in libraries Tyler Retzlaff
2024-03-20 22:01 ` [PATCH v7 1/4] net/i40e: use inline prefetch function Tyler Retzlaff
2024-03-26 10:16 ` Morten Brørup
2024-03-27 18:14 ` Tyler Retzlaff
2024-03-27 19:45 ` Morten Brørup
2024-03-20 22:01 ` [PATCH v7 2/4] mbuf: remove rte marker fields Tyler Retzlaff
2024-03-21 10:32 ` Bruce Richardson
2024-03-21 15:31 ` Tyler Retzlaff
2024-03-21 16:19 ` Morten Brørup
2024-03-26 11:12 ` Morten Brørup
2024-03-20 22:01 ` [PATCH v7 3/4] security: " Tyler Retzlaff
2024-03-26 10:28 ` Morten Brørup
2024-03-27 19:59 ` Tyler Retzlaff
2024-03-20 22:01 ` [PATCH v7 4/4] cryptodev: " Tyler Retzlaff
2024-03-26 10:31 ` Morten Brørup
2024-03-27 19:56 ` [PATCH v8 0/4] remove use of RTE_MARKER fields in libraries Tyler Retzlaff
2024-03-27 19:56 ` [PATCH v8 1/4] net/i40e: use inline prefetch function Tyler Retzlaff
2024-03-27 19:56 ` [PATCH v8 2/4] mbuf: remove rte marker fields Tyler Retzlaff
2024-03-27 19:56 ` [PATCH v8 3/4] security: " Tyler Retzlaff
2024-03-27 19:56 ` [PATCH v8 4/4] cryptodev: " Tyler Retzlaff
2024-04-02 20:08 ` [PATCH v9 0/4] remove use of RTE_MARKER fields in libraries Tyler Retzlaff
2024-04-02 20:08 ` [PATCH v9 1/4] net/i40e: use inline prefetch function Tyler Retzlaff
2024-04-02 20:08 ` [PATCH v9 2/4] mbuf: remove rte marker fields Tyler Retzlaff
2024-04-02 20:45 ` Stephen Hemminger
2024-04-02 20:51 ` Tyler Retzlaff
2024-04-02 20:08 ` [PATCH v9 3/4] security: " Tyler Retzlaff
2024-04-02 20:08 ` [PATCH v9 4/4] cryptodev: " Tyler Retzlaff
2024-04-03 17:53 ` [PATCH v10 0/4] remove use of RTE_MARKER fields in libraries Tyler Retzlaff
2024-04-03 17:53 ` [PATCH v10 1/4] net/i40e: use inline prefetch function Tyler Retzlaff
2024-04-03 21:49 ` Stephen Hemminger
2024-04-03 17:53 ` [PATCH v10 2/4] mbuf: remove rte marker fields Tyler Retzlaff
2024-04-03 19:32 ` Morten Brørup
2024-04-03 22:45 ` Tyler Retzlaff
2024-04-03 21:49 ` Stephen Hemminger
2024-04-03 17:53 ` [PATCH v10 3/4] security: " Tyler Retzlaff
2024-04-03 21:50 ` Stephen Hemminger
2024-04-03 17:53 ` [PATCH v10 4/4] cryptodev: " Tyler Retzlaff
2024-04-03 21:50 ` Stephen Hemminger
2024-04-04 17:51 ` [PATCH v11 0/4] remove use of RTE_MARKER fields in libraries Tyler Retzlaff
2024-04-04 17:51 ` [PATCH v11 1/4] net/i40e: use inline prefetch function Tyler Retzlaff
2024-04-04 17:51 ` [PATCH v11 2/4] mbuf: remove rte marker fields Tyler Retzlaff
2024-04-04 17:51 ` [PATCH v11 3/4] security: " Tyler Retzlaff
2024-04-04 17:51 ` [PATCH v11 4/4] cryptodev: " Tyler Retzlaff
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