From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
To: Rajesh Ravi <rajesh.ravi@broadcom.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 17:53:03 +0100 [thread overview]
Message-ID: <83009bb3-1e0c-a22e-eff8-41a437817cb7@intel.com> (raw)
In-Reply-To: <CAAr5zNeKyCBCEu2YFXMMDeTtxAfGa9UiT0xVVnDfrVfF+op+tg@mail.gmail.com>
On 18-Oct-19 11:54 AM, Rajesh Ravi wrote:
> + 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.
>
I'm not sure i'm following. You mean you *don't* want this mapping to be
performed?
--
Thanks,
Anatoly
next prev parent reply other threads:[~2019-10-18 16:53 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
2019-10-18 16:53 ` Burakov, Anatoly [this message]
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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