RE: Memory sharing between two primary processes

["Pathak, Pravin" <pravin.pathak@intel.com>]

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I did not use memif so can not comment on its performance. It all also depends upon what kind of communication is needed between processes.
Is it message based or simple shared memory structure. You should be able to allocate memory from hugepages and setup shared area.

Pravin

From: Kiran Khatke <kirankhatke23may@gmail.com>
Sent: Monday, June 6, 2022 9:56 AM
To: Pathak, Pravin <pravin.pathak@intel.com>
Cc: users@dpdk.org
Subject: Re: Memory sharing between two primary processes


Thanks Pravin.

Do you any comments over memif PMD performance?

Are there any better options than memif PMD in terms of performance?

Kiran


On Mon, Jun 6, 2022 at 6:53 AM Pathak, Pravin <pravin.pathak@intel.com<mailto:pravin.pathak@intel.com>> wrote:
Hi Kiran –
It should be possible. DPDK documentation  clearly shows two primary processes using memif to communicate.

32.2.1. Example: testpmd
In this example we run two instances of testpmd application and transmit packets over memif.
First create master interface:
#./build/app/testpmd -l 0-1 --proc-type=primary --file-prefix=pmd1 --vdev=net_memif,role=master -- -i

Now create slave interface (master must be already running so the slave will connect):
#./build/app/testpmd -l 2-3 --proc-type=primary --file-prefix=pmd2 --vdev=net_memif -- -i


From: Kiran Khatke <kirankhatke23may@gmail.com<mailto:kirankhatke23may@gmail.com>>
Sent: Monday, June 6, 2022 9:24 AM
To: Pathak, Pravin <pravin.pathak@intel.com<mailto:pravin.pathak@intel.com>>
Cc: users@dpdk.org<mailto:users@dpdk.org>
Subject: Re: Memory sharing between two primary processes

Hi Pravin,

Both are DPDK application, so want  to use DPDK Share memory i.e hugepages.

How to share memory between two independent (Primary) application?  Does memif PMD allows that ?

Thanks,
Kiran

On Mon, Jun 6, 2022 at 5:58 AM Pathak, Pravin <pravin.pathak@intel.com<mailto:pravin.pathak@intel.com>> wrote:
Hi Kiran –
Can your application create and manage shared memory on it own without using DPDK support ?
Regards
Pravin

From: Kiran Khatke <kirankhatke23may@gmail.com<mailto:kirankhatke23may@gmail.com>>
Sent: Monday, June 6, 2022 2:26 AM
To: users@dpdk.org<mailto:users@dpdk.org>
Subject: Memory sharing between two primary processes


Hi,



Per DPDK Multiprocess, we know that, it is possible to share memory(hugepages) between a primary and secondary Process.  Primary process allocates the memory and that is accessible by the secondary (both are using same  "--file-prefix=" parameter).



There is a need in our application, to have two primary processes (started with different file-prefix) and would like to know the options - To share memory (hugepage) between two primaries and which can give us better throughputs.



During exploration, got to know about memif PMD, which allows for DPDK and any other client using memif (DPDK, libmemif) to communicate over shared memory.

Do you have any comments about memif performance ? Are there better options over memif to share memory between two primaries ?



Thanks ,

Kiran

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