Re: [dpdk-dev] [PATCH] net/dpdkoin: add new driver

[Kevin Traynor <ktraynor@redhat.com>]

On 01/04/2020 14:10, Matteo Croce wrote:
> DPDK polls the packet in a busy loop. This means that CPU constantly spins
> looking for packets, regardless of the network traffic.
> DPDK does this to reduce latency and avoid using interrupts, at expense of
> efficiency: this might consume more processing power and generate more heat
> than needed, potentially increasing the TCO of a DPDK appliance.
> 
> Here comes DPDKoin. DPDKoin is a DPDK PMD, which instead of moving
> packets, mines cryptocurrencies.
> DPDKoin just does a few calculations to every poll cycle, this means that
> when the network is loaded, DPDKoin consumes just a few cycles, but when
> there is no traffic, DPDKoin mines currencies in a busy loop.
> The coins are mined with no extra consumption, as the CPU would spin
> anyway.
> 
> This is a system running with two 10G cards running with DPDK:
> 
>   PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
>  8223 root      10 -10  260.6g 597516  19100 S 199.8   0.5   0:17.89 testpmd
> 
> And this is the same system with a DPDKoin port added:
> 
>   PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
>  9438 root      10 -10  260.6g 598892  19800 S 199.8   0.5   0:19.43 testpmd
> 
> As you can see, we don't observe any change in the CPU usage, and besides,
> the earned coins lowers the appliance TCO.
> 
> Just for reference, a test run log follows:
> 
> $ sudo testpmd --no-huge -m 1024 --no-pci --vdev eth_dpdkoin0 --vdev eth_dpdkoin1
> EAL: Detected 8 lcore(s)
> EAL: Detected 1 NUMA nodes
> EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
> EAL: Selected IOVA mode 'VA'
> EAL: Probing VFIO support...
> testpmd: create a new mbuf pool <mbuf_pool_socket_0>: n=203456, size=2176, socket=0
> testpmd: preferred mempool ops selected: ring_mp_mc
> Configuring Port 0 (socket 0)
> Port 0: 4A:50:3C:33:55:21
> Configuring Port 1 (socket 0)
> Port 1: BA:BB:0A:BB:0C:CA
> Checking link statuses...
> Done
> No commandline core given, start packet forwarding
> io packet forwarding - ports=2 - cores=1 - streams=2 - NUMA support enabled, MP allocation mode: native
> Logical Core 1 (socket 0) forwards packets on 2 streams:
>   RX P=0/Q=0 (socket 0) -> TX P=1/Q=0 (socket 0) peer=02:00:00:00:00:01
>   RX P=1/Q=0 (socket 0) -> TX P=0/Q=0 (socket 0) peer=02:00:00:00:00:00
> 
>   io packet forwarding packets/burst=32
>   nb forwarding cores=1 - nb forwarding ports=2
>   port 0: RX queue number: 1 Tx queue number: 1
>     Rx offloads=0x0 Tx offloads=0x0
>     RX queue: 0
>       RX desc=0 - RX free threshold=0
>       RX threshold registers: pthresh=0 hthresh=0  wthresh=0
>       RX Offloads=0x0
>     TX queue: 0
>       TX desc=0 - TX free threshold=0
>       TX threshold registers: pthresh=0 hthresh=0  wthresh=0
>       TX offloads=0x0 - TX RS bit threshold=0
>   port 1: RX queue number: 1 Tx queue number: 1
>     Rx offloads=0x0 Tx offloads=0x0
>     RX queue: 0
>       RX desc=0 - RX free threshold=0
>       RX threshold registers: pthresh=0 hthresh=0  wthresh=0
>       RX Offloads=0x0
>     TX queue: 0
>       TX desc=0 - TX free threshold=0
>       TX threshold registers: pthresh=0 hthresh=0  wthresh=0
>       TX offloads=0x0 - TX RS bit threshold=0
> libbitcoin 0.1: mining on CPU2
> libbitcoin 0.1: mining on CPU4
> ---
>  config/common_base                            |   5 +
>  drivers/net/Makefile                          |   1 +
>  drivers/net/dpdkoin/Makefile                  |  23 +
>  drivers/net/dpdkoin/meson.build               |   3 +
>  drivers/net/dpdkoin/rte_eth_dpdkoin.c         | 696 ++++++++++++++++++
>  .../net/dpdkoin/rte_pmd_dpdkoin_version.map   |   3 +
>  mk/rte.app.mk                                 |   1 +
>  7 files changed, 732 insertions(+)
>  create mode 100644 drivers/net/dpdkoin/Makefile
>  create mode 100644 drivers/net/dpdkoin/meson.build
>  create mode 100644 drivers/net/dpdkoin/rte_eth_dpdkoin.c
>  create mode 100644 drivers/net/dpdkoin/rte_pmd_dpdkoin_version.map

I see you are requesting this for backport to stable branches. While
this is not fixing a specific commit per se, it is clearly fixing a gap
whereby it would be unfair for stable users to miss out on any potential
bonanza.

Unfortunately there is a blocker due to validation. Normally, we might
be concerned by lack of it, but in this case the concern is that it
might encourage too much validation and many lengthy stress tests that
could impact release dates.