From: Bruce Richardson <bruce.richardson@intel.com>
To: "Morten Brørup" <mb@smartsharesystems.com>
Cc: Shijith Thotton <sthotton@marvell.com>,
stephen@networkplumber.org, olivier.matz@6wind.com, dev@dpdk.org,
jerinj@marvell.com, thomas@monjalon.net,
Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
Subject: Re: [PATCH] mbuf: add mbuf physical address field to dynamic field
Date: Mon, 4 Jul 2022 15:00:37 +0100 [thread overview]
Message-ID: <YsLyhTNSSLN9vAv+@bricha3-MOBL.ger.corp.intel.com> (raw)
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35D871A4@smartserver.smartshare.dk>
On Sun, Jul 03, 2022 at 09:31:01AM +0200, Morten Brørup wrote:
> > From: Shijith Thotton [mailto:sthotton@marvell.com]
> > Sent: Friday, 1 July 2022 14.25
> >
> > >> If all devices are configured to run in IOVA mode as VA, physical
> > >> address field of mbuf (buf_iova) won't be used.
>
> Will some of the hardware vendors please comment on this: Has IOVA VA mode become common over time, or is it still an exotic bleeding edge feature?
>
> If it has become common, we should let DPDK evolve accordingly, and consider PA (non-VA) mode legacy, treating it as such. Don't get stuck in the past.
>
IOVA as VA mode is indeed common and we are constantly encouraging users to
switch to using vfio to try and take advantage of this.
However, in my experience IOVA as PA is still very, very common too. We
cannot drop support for this mode just yet, unfortunately.
> > >> In such cases,
> > buf_iova
> > >> space is free to use as a dynamic field. So a new dynamic field
> > member
> > >> (dynfield2) is added in mbuf structure to make use of that space.
> > >>
> > >> A new mbuf flag RTE_MBUF_F_DYNFIELD2 is introduced to help identify
> > the
> > >> mbuf that can use dynfield2.
> > >>
> > >> Signed-off-by: Shijith Thotton <sthotton@marvell.com>
> > >
> > > This seems like a complex and potentially error prone way to do this.
>
> Perhaps this optimization should be a compile time option instead?
>
It could indeed be, and probably could be done very safely, in that we could
mark as disabled all drivers when the mode is enabled for a build.
Thereafter, drivers could be marked as VA-only safe as they are updated as
necessary, i.e. use the build system to enforce that only drivers known to
work with the mode are built when the mode is enabled.
That said, verifying all drivers to work with this mode is a decent effort.
Do we have indications of the perf benefit we would get from doing this for
some real-world app?
/Bruce
next prev parent reply other threads:[~2022-07-04 14:00 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-30 16:25 Shijith Thotton
2022-06-30 16:45 ` Stephen Hemminger
2022-07-01 12:16 ` Shijith Thotton
2022-07-01 12:24 ` Shijith Thotton
2022-07-03 7:31 ` Morten Brørup
2022-07-04 14:00 ` Bruce Richardson [this message]
2022-08-03 15:34 ` [EXT] " Shijith Thotton
2022-08-29 15:16 ` [PATCH v1 0/4] mbuf dynamic field expansion Shijith Thotton
2022-09-07 13:43 ` [PATCH v2 0/5] " Shijith Thotton
2022-09-21 9:43 ` David Marchand
2022-09-21 14:01 ` [EXT] " Shijith Thotton
2022-09-21 13:56 ` [PATCH v3 " Shijith Thotton
2022-09-21 13:56 ` [PATCH v3 1/5] build: add meson option to configure IOVA mode as VA Shijith Thotton
2022-09-28 12:52 ` Olivier Matz
2022-09-29 5:48 ` [EXT] " Shijith Thotton
2022-09-21 13:56 ` [PATCH v3 2/5] mbuf: add second dynamic field member for VA only build Shijith Thotton
2022-09-28 7:24 ` Thomas Monjalon
2022-09-28 12:52 ` Olivier Matz
2022-09-28 19:33 ` Thomas Monjalon
2022-09-28 19:48 ` Stephen Hemminger
2022-09-29 6:13 ` [EXT] " Shijith Thotton
2022-09-28 12:52 ` Olivier Matz
2022-09-21 13:56 ` [PATCH v3 3/5] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-09-21 14:07 ` Morten Brørup
2022-09-28 12:52 ` Olivier Matz
2022-09-29 6:14 ` [EXT] " Shijith Thotton
2022-09-21 13:56 ` [PATCH v3 4/5] drivers: mark Marvell cnxk PMDs work with IOVA as VA Shijith Thotton
2022-09-28 12:53 ` Olivier Matz
2022-09-29 6:19 ` [EXT] " Shijith Thotton
2022-09-29 7:44 ` Olivier Matz
2022-09-29 8:10 ` Shijith Thotton
2022-10-07 20:17 ` Olivier Matz
2022-10-07 20:22 ` [EXT] " Shijith Thotton
2022-09-21 13:56 ` [PATCH v3 5/5] drivers: mark software " Shijith Thotton
2022-09-28 5:41 ` [PATCH v3 0/5] mbuf dynamic field expansion Shijith Thotton
2022-09-28 12:52 ` Olivier Matz
2022-09-29 4:51 ` [EXT] " Shijith Thotton
2022-10-07 13:50 ` Thomas Monjalon
2022-10-07 19:35 ` [EXT] " Shijith Thotton
2022-10-07 19:30 ` [PATCH v4 0/7] " Shijith Thotton
2022-10-07 19:30 ` [PATCH v4 1/7] mbuf: add API to get and set mbuf physical address Shijith Thotton
2022-10-07 20:16 ` Olivier Matz
2022-10-07 20:20 ` [EXT] " Shijith Thotton
2022-10-07 19:30 ` [PATCH v4 2/7] test/dma: use API to get mbuf data " Shijith Thotton
2022-10-07 20:17 ` Olivier Matz
2022-10-07 19:30 ` [PATCH v4 3/7] build: add meson option to configure IOVA mode as PA Shijith Thotton
2022-10-07 19:30 ` [PATCH v4 4/7] mbuf: add second dynamic field member Shijith Thotton
2022-10-07 19:30 ` [PATCH v4 5/7] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-10-07 19:30 ` [PATCH v4 6/7] drivers: mark cnxk PMDs work with IOVA as PA disabled Shijith Thotton
2022-10-07 19:30 ` [PATCH v4 7/7] drivers: mark software " Shijith Thotton
2022-10-07 20:19 ` [PATCH v4 0/7] mbuf dynamic field expansion Olivier Matz
2022-10-07 21:02 ` [PATCH v5 " Shijith Thotton
2022-10-07 21:02 ` [PATCH v5 1/7] mbuf: add API to get and set mbuf physical address Shijith Thotton
2022-10-07 21:20 ` Stephen Hemminger
2022-10-07 21:02 ` [PATCH v5 2/7] test/dma: use API to get mbuf data " Shijith Thotton
2022-10-07 21:02 ` [PATCH v5 3/7] build: add meson option to configure IOVA mode as PA Shijith Thotton
2022-10-07 21:02 ` [PATCH v5 4/7] mbuf: add second dynamic field member Shijith Thotton
2022-10-07 21:02 ` [PATCH v5 5/7] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-10-07 21:22 ` Stephen Hemminger
2022-10-07 21:30 ` [EXT] " Shijith Thotton
2022-10-07 21:02 ` [PATCH v5 6/7] drivers: mark cnxk PMDs work with IOVA as PA disabled Shijith Thotton
2022-10-07 21:02 ` [PATCH v5 7/7] drivers: mark software " Shijith Thotton
2022-10-09 9:34 ` [PATCH v5 0/7] mbuf dynamic field expansion Thomas Monjalon
2022-09-07 13:43 ` [PATCH v2 1/5] build: add meson option to configure IOVA mode as VA Shijith Thotton
2022-09-07 15:31 ` Stephen Hemminger
2022-09-07 15:38 ` Bruce Richardson
2022-09-07 21:33 ` Morten Brørup
2022-09-07 13:43 ` [PATCH v2 2/5] mbuf: add second dynamic field member for VA only build Shijith Thotton
2022-09-07 13:43 ` [PATCH v2 3/5] lib: move mbuf next pointer to first cache line Shijith Thotton
2022-09-07 13:43 ` [PATCH v2 4/5] drivers: mark Marvell cnxk PMDs work with IOVA as VA Shijith Thotton
2022-09-07 13:43 ` [PATCH v2 5/5] drivers: mark software " Shijith Thotton
2022-08-29 15:16 ` [PATCH v1 1/4] build: add meson option to configure IOVA mode " Shijith Thotton
2022-08-29 18:18 ` Morten Brørup
2022-08-30 8:32 ` Bruce Richardson
2022-08-29 15:16 ` [PATCH v1 2/4] mbuf: add second dynamic field member for VA only build Shijith Thotton
2022-08-29 18:32 ` Morten Brørup
2022-08-30 8:35 ` Bruce Richardson
2022-08-30 8:41 ` [EXT] " Pavan Nikhilesh Bhagavatula
2022-08-30 13:22 ` Honnappa Nagarahalli
2022-09-07 13:55 ` Shijith Thotton
2022-08-29 15:16 ` [PATCH v1 3/4] drivers: mark Marvell cnxk PMDs work with IOVA as VA Shijith Thotton
2022-08-29 15:16 ` [PATCH v1 4/4] drivers: mark software " Shijith Thotton
2022-08-30 13:07 ` [PATCH] mbuf: add mbuf physical address field to dynamic field Ferruh Yigit
2022-09-12 13:19 ` [EXT] " Shijith Thotton
2022-06-30 16:55 ` Bruce Richardson
2022-07-01 9:48 ` Olivier Matz
2022-07-01 11:53 ` Slava Ovsiienko
2022-07-01 12:01 ` [EXT] " Shijith Thotton
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