DPDK patches and discussions
 help / color / mirror / Atom feed
From: Morten Brørup <mb@smartsharesystems.com>
To: "Honnappa Nagarahalli" <Honnappa.Nagarahalli@arm.com>,
	"Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	"Dharmik Thakkar" <Dharmik.Thakkar@arm.com>,
	"Olivier Matz" <olivier.matz@6wind.com>,
	"Andrew Rybchenko" <andrew.rybchenko@oktetlabs.ru>
Cc: <dev@dpdk.org>, "nd" <nd@arm.com>,
	"Ruifeng Wang" <Ruifeng.Wang@arm.com>, "nd" <nd@arm.com>,
	"nd" <nd@arm.com>
Subject: Re: [dpdk-dev] [RFC] mempool: implement index-based per core cache
Date: Sun, 31 Oct 2021 09:14:06 +0100
Message-ID: <98CBD80474FA8B44BF855DF32C47DC35D86C83@smartserver.smartshare.dk> (raw)
In-Reply-To: <DBAPR08MB5814FAB214D809E9E82DB9EF98AE9@DBAPR08MB5814.eurprd08.prod.outlook.com>

> From: Morten Brørup
> Sent: Saturday, 30 October 2021 12.24
> 
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Honnappa
> > Nagarahalli
> > Sent: Monday, 4 October 2021 18.36
> >
> > <snip>
> > >
> > >
> > > > > > Current mempool per core cache implementation is based on
> > pointer
> > > > > > For most architectures, each pointer consumes 64b Replace it
> > with
> > > > > > index-based implementation, where in each buffer is addressed
> > by
> > > > > > (pool address + index)
> 
> I like Dharmik's suggestion very much. CPU cache is a critical and
> limited resource.
> 
> DPDK has a tendency of using pointers where indexes could be used
> instead. I suppose pointers provide the additional flexibility of
> mixing entries from different memory pools, e.g. multiple mbuf pools.
> 
> > > > >
> > > > > I don't think it is going to work:
> > > > > On 64-bit systems difference between pool address and it's elem
> > > > > address could be bigger than 4GB.
> > > > Are you talking about a case where the memory pool size is more
> > than 4GB?
> > >
> > > That is one possible scenario.
> 
> That could be solved by making the index an element index instead of a
> pointer offset: address = (pool address + index * element size).

Or instead of scaling the index with the element size, which is only known at runtime, the index could be more efficiently scaled by a compile time constant such as RTE_MEMPOOL_ALIGN (= RTE_CACHE_LINE_SIZE). With a cache line size of 64 byte, that would allow indexing into mempools up to 256 GB in size.

> 
> > > Another possibility - user populates mempool himself with some
> > external
> > > memory by calling rte_mempool_populate_iova() directly.
> > Is the concern that IOVA might not be contiguous for all the memory
> > used by the mempool?
> >
> > > I suppose such situation can even occur even with normal
> > > rte_mempool_create(), though it should be a really rare one.
> > All in all, this feature needs to be configurable during compile
> time.


  parent reply	other threads:[~2021-10-31  8:14 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-30 17:27 Dharmik Thakkar
2021-10-01 12:36 ` Jerin Jacob
2021-10-01 15:44   ` Honnappa Nagarahalli
2021-10-01 17:32     ` Jerin Jacob
2021-10-01 17:57       ` Honnappa Nagarahalli
2021-10-01 18:21       ` Jerin Jacob
2021-10-01 21:30 ` Ananyev, Konstantin
2021-10-02  0:07   ` Honnappa Nagarahalli
2021-10-02 18:51     ` Ananyev, Konstantin
2021-10-04 16:36       ` Honnappa Nagarahalli
2021-10-30 10:23         ` Morten Brørup
2021-10-31  8:14         ` Morten Brørup [this message]
2021-11-03 15:12           ` Dharmik Thakkar
2021-11-03 15:52             ` Morten Brørup
2021-11-04  4:42               ` Dharmik Thakkar
2021-11-04  8:04                 ` Morten Brørup
2021-11-08  4:32                   ` Honnappa Nagarahalli
2021-11-08  7:22                     ` Morten Brørup
2021-11-08 15:29                       ` Honnappa Nagarahalli
2021-11-08 15:39                         ` Morten Brørup
2021-11-08 15:46                           ` Honnappa Nagarahalli
2021-11-08 16:03                             ` Morten Brørup
2021-11-08 16:47                               ` Jerin Jacob
2021-12-24 22:59 ` [PATCH 0/1] " Dharmik Thakkar
2021-12-24 22:59   ` [PATCH 1/1] " Dharmik Thakkar
2022-01-11  2:26     ` Ananyev, Konstantin
2022-01-13  5:17       ` Dharmik Thakkar
2022-01-13 10:37         ` Ananyev, Konstantin
2022-01-19 15:32           ` Dharmik Thakkar
2022-01-21 11:25             ` Ananyev, Konstantin
2022-01-21 11:31               ` Ananyev, Konstantin
2022-03-24 19:51               ` Dharmik Thakkar
2021-12-25  0:16   ` [PATCH 0/1] " Morten Brørup
2022-01-07 11:15     ` Bruce Richardson
2022-01-07 11:29       ` Morten Brørup
2022-01-07 13:50         ` Bruce Richardson
2022-01-08  9:37           ` Morten Brørup
2022-01-10  6:38             ` Jerin Jacob
2022-01-13  5:31               ` Dharmik Thakkar
2022-01-13  5:36   ` [PATCH v2 " Dharmik Thakkar
2022-01-13  5:36     ` [PATCH v2 1/1] " Dharmik Thakkar
2022-01-13 10:18       ` Jerin Jacob
2022-01-20  8:21       ` Morten Brørup
2022-01-21  6:01         ` Honnappa Nagarahalli
2022-01-21  7:36           ` Morten Brørup
2022-01-24 13:05             ` Ray Kinsella
2022-01-21  9:12           ` Bruce Richardson
2022-01-23  7:13       ` Wang, Haiyue

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=98CBD80474FA8B44BF855DF32C47DC35D86C83@smartserver.smartshare.dk \
    --to=mb@smartsharesystems.com \
    --cc=Dharmik.Thakkar@arm.com \
    --cc=Honnappa.Nagarahalli@arm.com \
    --cc=Ruifeng.Wang@arm.com \
    --cc=andrew.rybchenko@oktetlabs.ru \
    --cc=dev@dpdk.org \
    --cc=konstantin.ananyev@intel.com \
    --cc=nd@arm.com \
    --cc=olivier.matz@6wind.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror http://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ http://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git