From: Rajesh Ravi <rajesh.ravi@broadcom.com>
To: "Burakov, Anatoly" <anatoly.burakov@intel.com>
Cc: Ajit Khaparde <ajit.khaparde@broadcom.com>,
dev@dpdk.org,
Jonathan Richardson <jonathan.richardson@broadcom.com>,
Scott Branden <scott.branden@broadcom.com>,
Vikram Mysore Prakash <vikram.prakash@broadcom.com>,
Srinath Mannam <srinath.mannam@broadcom.com>
Subject: Re: [dpdk-dev] [PATCH] eal: add option --iso-cmem for external custom memory
Date: Fri, 18 Oct 2019 16:24:11 +0530 [thread overview]
Message-ID: <CAAr5zNeKyCBCEu2YFXMMDeTtxAfGa9UiT0xVVnDfrVfF+op+tg@mail.gmail.com> (raw)
In-Reply-To: <da983f2b-0ad6-fe2e-c83a-599b3168e1fb@intel.com>
+ Srinath
Thanks Anatoly for reviewing this. Please find my reply inline below:
[Anatoly] First of all, what is "iso-cmem"? It doesn't seem to have any
defined
meaning nor any relation to any existing functionality, and it's not
explained anywhere what is "isolated cmem".
[Rajesh] I 'll correct commit message to include clearer explanation.
*Context & purpose*
We 're using this to improve SPDK performance. When NVMe completion queues
are allocated from a certain memory range,
out of order competions completions are enabled with our PCIe and it
improves performance.
*Usage*
spdk_env_init()-->(calls rte_eal_init(), and then calls
)spdk_env_dpdk_post_init() [file: spdk/lib/env_dpdk/init.c]
--> spdk_mem_map_init() [lib/env_dpdk/memory.c]-->map_cmem_virtual_area()
[this is our custom function]
In map_cmem_virtual_area(): we 're mmaping anonymous & private region and
then creating iova table which makes iova addresses which fall in custom
memory region.
Then we call rte_malloc_heap_memory_add() and then allocate NVMe completion
queues from this heap.
[Anatoly] More importantly, why is this necessary? Type1 map only bypasses
external segments when adding memory at startup - it doesn't stop you
from calling rte_vfio_dma_map() to map the memory with VFIO when you
create the segment.
[Rajesh] Please correct me if I'm wrong or missing some thing here.
A) We wanted to create a heap from which we can allocate dynamically
B) I see that type1_map()
[file:dpdk/lib/librte_eal/linuxapp/eal/eal_vfio.c] getting called once
rte_malloc_heap_memory_add()() was invoked.
SPDK uses type1 dma map [spdk/lib/env_dpdk/memory.c]
vfio_type1_dma_map() is registered for .dma_map_func member
[dpdk/lib/librte_eal/linuxapp/eal/eal_vfio.c]
So type1_map is called. Not sure whether we can change this.
Regards,
Rajesh
On Thu, Oct 17, 2019 at 9:15 PM Burakov, Anatoly <anatoly.burakov@intel.com>
wrote:
> On 15-Oct-19 6:30 AM, Ajit Khaparde wrote:
> > From: Rajesh Ravi <rajesh.ravi@broadcom.com>
> >
> > Support external custom memory added to heap to be used with vfio with
> > --iso-cmem option.Type1 memory mapping was by passed for external memory.
> > But an exception is added to allow external custom memory to be used with
> > vfio.
> >
> > Signed-off-by: Rajesh Ravi <rajesh.ravi@broadcom.com>
> > Reviewed-by: Jonathan Richardson <jonathan.richardson@broadcom.com>
> > Reviewed-by: Scott Branden <scott.branden@broadcom.com>
> > Reviewed-by: Vikram Mysore Prakash <vikram.prakash@broadcom.com>
> > Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
> > ---
>
> Hi,
>
> First of all, what is "iso-cmem"? It doesn't seem to have any defined
> meaning nor any relation to any existing functionality, and it's not
> explained anywhere what is "isolated cmem".
>
> More importantly, why is this necessary? Type1 map only bypasses
> external segments when adding memory at startup - it doesn't stop you
> from calling rte_vfio_dma_map() to map the memory with VFIO when you
> create the segment.
>
> --
> Thanks,
> Anatoly
>
--
Regards,
Rajesh
next prev parent reply other threads:[~2019-10-21 7:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-15 5:30 Ajit Khaparde
2019-10-17 15:45 ` Burakov, Anatoly
2019-10-18 10:54 ` Rajesh Ravi [this message]
2019-10-18 16:53 ` Burakov, Anatoly
2019-10-21 15:46 ` Rajesh Ravi
2019-10-22 7:56 ` Rajesh Ravi
2019-10-24 11:43 ` Burakov, Anatoly
2019-10-25 12:53 ` Rajesh Ravi
2019-10-25 15:02 ` Burakov, Anatoly
2019-10-30 19:50 ` Rajesh Ravi
2019-11-04 10:25 ` Burakov, Anatoly
2019-11-05 11:41 ` Burakov, Anatoly
2019-11-05 14:10 ` Rajesh Ravi
2019-11-05 15:18 ` Burakov, Anatoly
2019-11-05 17:13 ` Burakov, Anatoly
2019-11-06 13:55 ` David Marchand
2019-11-07 15:51 ` David Marchand
2019-11-07 16:16 ` Rajesh Ravi
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