I am using af_packet... I will try dpdk.
On Fri, Jul 7, 2017 at 6:11 PM, Florin Coras <fcoras.li...@gmail.com> wrote:
> Hi Yuliang,
>
> Are you running with dpdk or with tap/af_packet interfaces? As far as I
> remember multithreading for the last two might not work properly.
>
> Florin
>
> On Jul 7, 2017, at 5:55 PM, Yuliang Li <yuliang...@yale.edu> wrote:
>
> I printed 3 thread_index, and all 3 shows the same value:
>
> 1. vlib_frame_t's thread_index:
> For each pending frame p:
>
> vlib_pending_frame_t *p = nm->pending_frames + i;
>
> I get the vlib_frame_t f:
>
> vlib_frame_t *f = vlib_get_frame (vm, p->frame_index);
>
> and I print f->thread_index
>
> 2. vlib_node_runtime_t's thread_indes:
> For each pending frame p, I get its node runtime nr:
>
> vlib_node_runtime_t *nr = vec_elt_at_index
> (nm->nodes_by_type[VLIB_NODE_TYPE_INTERNAL],
> p->node_runtime_index);
>
> and I print nr->thread_index
>
> 3. vlib_main_t's thread_index:
> I print vm->thread_index
>
>
> On Fri, Jul 7, 2017 at 5:37 PM, Dave Barach (dbarach) <dbar...@cisco.com>
> wrote:
>
>> What exactly were you printing? Vlib_pending_frame_t’s don’t have a
>> thread_index field...:
>>
>>
>>
>>
>>
>> /* A frame pending dispatch by main loop. */
>>
>> typedef struct
>>
>> {
>>
>> /* Node and runtime for this frame. */
>>
>> u32 node_runtime_index;
>>
>>
>>
>> /* Frame index (in the heap). */
>>
>> u32 frame_index;
>>
>>
>>
>> /* Start of next frames for this node. */
>>
>> u32 next_frame_index;
>>
>>
>>
>> /* Special value for next_frame_index when there is no next frame. */
>>
>> #define VLIB_PENDING_FRAME_NO_NEXT_FRAME ((u32) ~0)
>>
>> } vlib_pending_frame_t;
>>
>>
>>
>> Thanks… Dave
>>
>>
>>
>> *From:* Yuliang Li [mailto:yuliang...@yale.edu]
>> *Sent:* Friday, July 7, 2017 8:04 PM
>> *To:* Dave Barach (dbarach) <dbar...@cisco.com>
>> *Cc:* vpp-dev@lists.fd.io
>> *Subject:* Re: [vpp-dev] set mapping from node to thread
>>
>>
>>
>> Hi Dave,
>>
>>
>>
>> Thanks for the detailed response.
>>
>>
>>
>> However, from the experiment I did, I see the same packet being processed
>> by two threads. That is why I asked this question. Maybe I made some
>> mistakes, here is what I did:
>>
>>
>>
>> - In *vlib_main_or_worker_loop* function, I print out all pending frames
>> here, as well as the thread_index of them, and the node name.
>>
>> - I start the vpp with 4 worker threads, and set up SNAT according to the
>> progressive tutorial
>> <https://wiki.fd.io/view/VPP/Progressive_VPP_Tutorial>.
>>
>> - I run iperf that go through the SNAT.
>>
>>
>>
>> The printed information shows that, each TCP packet from the inside to
>> the outside of the SNAT will go through the ethernet-input and snat-in2out.
>> But the thread_index at the ethernet-input is 2, while the thread_index at
>> snat-in2out is 1.
>>
>>
>>
>> Is the above expected?
>>
>>
>>
>> Thanks,
>>
>>
>>
>> On Fri, Jul 7, 2017 at 12:22 PM, Dave Barach (dbarach) <dbar...@cisco.com>
>> wrote:
>>
>> Dear Yuliang,
>>
>>
>>
>> From a high level: vpp creates N identical graph replicas in a multi-core
>> configuration. When practicable, we use hardware RSS hashing to ensure that
>> all packets belonging to a specific flow are processed [in order!] by the
>> same thread / graph replica. In effect, embarrassing parallelism.
>>
>>
>>
>> It’s easy enough to hand off packets between threads - see the
>> “handoff-node” - but we avoid that whenever possible.
>>
>>
>>
>> Although one could - and I have - divided graph nodes across threads to
>> create pipelines, that scheme needs significant dynamic tuning to handle a
>> traffic pattern change. It’s hard to map nodes onto cores so that each
>> thread in a pipeline uses approximately the same number of clocks/pkt;
>> critical, since pipelines run at the speed of the slowest stage.
>>
>>
>>
>> It’s possible to hand off a full frame of packets for less than two
>> clocks/pkt. Unfortunately, that’s the least significant issue. Handing off
>> a packet from one core/thread to another guarantees a bunch of memory/cache
>> subsystem pressure as the system moves packet data and metadata from A to
>> B.
>>
>>
>>
>> HTH... Dave
>>
>>
>>
>> *From:* vpp-dev-boun...@lists.fd.io [mailto:vpp-dev-boun...@lists.fd.io] *On
>> Behalf Of *Yuliang Li
>> *Sent:* Friday, July 7, 2017 1:14 PM
>> *To:* vpp-dev@lists.fd.io
>> *Subject:* [vpp-dev] set mapping from node to thread
>>
>>
>>
>> Hi,
>>
>>
>>
>> Is there a way to set which node should run on which thread? And is there
>> a command that shows the mapping from nodes to threads?
>>
>>
>>
>> Thanks,
>>
>> --
>>
>> Yuliang Li
>>
>> PhD student
>>
>> Department of Computer Science
>>
>> Yale University
>>
>>
>>
>>
>>
>> --
>>
>> Yuliang Li
>>
>> PhD student
>>
>> Department of Computer Science
>>
>> Yale University
>>
>
>
>
> --
> Yuliang Li
> PhD student
> Department of Computer Science
> Yale University
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>
>
>
--
Yuliang Li
PhD student
Department of Computer Science
Yale University
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