Editing zhaoxin/microarchitectures/wudaokou

{{zhaoxin title|WuDaoKou|arch}}
{{microarchitecture
|atype=CPU
|name=WuDaoKou
|designer=Zhaoxin
|manufacturer=HLMC
|manufacturer 2=SMIC
|introduction=December 28, 2017
|process=28 nm
|cores=2
|cores 2=4
|cores 3=8
|type=Superscalar
|oooe=Yes
|speculative=Yes
|renaming=Yes
|stages=18
|isa=x86-64
|feature=SM3
|feature 2=SM4
|extension=MMX
|extension 2=SSE
|extension 3=SSE2
|extension 4=SSE3
|extension 5=SSSE3
|extension 6=SSE4.1
|extension 7=SSE4.2
|extension 8=AVX
|extension 9=AVX2
|extension 10=AES
|extension 11=RDRND
|extension 12=BMI
|extension 13=BMI2
|extension 14=TXT
|extension 15=RDSEED
|l1i=32 KiB
|l1i per=core
|l1i desc=8-way set associative
|l1d=32 KiB
|l1d per=core
|l1d desc=8-way set associative
|l2=4 MiB
|l2 per=cluster
|l2 desc=8-way set associative
|predecessor=Zhangjiang
|predecessor link=zhaoxin/microarchitectures/zhangjiang
|successor=LuJiaZui
|successor link=zhaoxin/microarchitectures/lujiazui
}}
'''WuDaoKou''' is the successor to {{\\|Zhangjiang}}, a [[28 nm]] [[x86]] microarchitecture designed by [[Zhaoxin]] for mainstream laptops, desktops, and servers.

== Etymology ==
WuDaoKou is named after the [[wikipedia:Wudaokou Station|Wudaokou Station]] of the Beijing Subway in China.

== Brands ==
{| class="wikitable"
! Family !! Series !! Description
|-
| {{zhaoxin|KaiXian}} || KX (5000) || Desktop, Laptops
|-
| {{zhaoxin|KaisHeng}} || KH (20000) || Storage, Servers
|}

<div>
<div style="float:left;">[[File:hk-20000.png|450px]]&nbsp;</div>
<div style="float:left;">[[File:kx-5000.png|450px]]</div>
</div>

{{clear}}

== Release Dates ==
[[File:zhaoxin roadmap (2017).png|right|400px]]
Development for WuDaoKou started in August 2013. The basic architecture design was completed by June 2014 with basic design done in July 2015. WuDaoKou hardware implementation was completed in April 2016 and [[taped out]] in August 2016. Final verification was done in October 2016 and mass production started in October 2017. The KX-5000 (formerly ZX-D) was announced at Semicon China 2017. The architecture and SKUs were officially unveiled at a conference on December 28, 2017.

[[File:wudaokou timeline.png|500px]]

WuDaoKou is said to be a result of 9,000 engineering months. Development data exceeded 200 TB with 4,000 cores being used for simulations with ten hardware emulators used for verification simulating a total of 150 billion instructions testing more than 300 different kinds of software, testing the CPU, GPU, memory controller, and bus.

{{clear}}

== Process Technology ==
WuDaoKou is manufactured on [[HLMC]]'s [[28 nm process]].

== Architecture ==

=== Key changes from {{\\|Zhangjiang}} ===
[[File:WuDaoKou performance.png|right|450px]]
* 25% higher [[IPC]]
* 140% higher performance in multi-threaded workloads
* [[8 cores]] per die (up from 4)
* SoC design
** New [[Uncore]]
*** [[northbridge]] moved on-die
*** [[PCIe]] 3.0 (from 2.0)
*** [[DDR4]] (From [[DDR3]])
** New [[integrated graphics processor]]
*** HD Audio Output/Codec
*** DirectX 11.1
*** Up to 3 displays
**** DP (1.2a) / eDP (1.3) / HDMI (1.4b) / VGA
* Core
** Improved OoOE algorithm
** Pipeline was reduced by 5 stages
** Execution engines were re-balanced
** Branch prediction unit was reworked and optimized
* [[FSB]] removed
** x4 PCIe 3.0 communication with [[southbridge]] chipset
* Chipset
** Gigabit Ethernet port (RGMII)
** USB 3.1 Gen2 (Type-C) ports
** SATA 3.0 ports
* Formal OS certification
** Windows Hardware Quality Labs (WHQL) certification
*** Windows 7/10
{{expand list}}

=== Block Diagram ===
{{empty section}}

=== Memory Hierarchy ===
* Cache
** L1D Cache
*** 32 KiB, 8-way set associative
*** Per core
** L1I Cache
*** 32 KiB, 8-way set associative
*** Per core
** L2 Cache
*** 4/8 MiB, 16/32-way set associative
*** Per quad-core cluster
* System DRAM
** 2 Channels
** DDR4, Up to 2400 MT/s

== Overview ==
[[File:wudaokou overview.svg|right|350px]]
WuDaoKou is largely a brand new architecture designed by Zhaoxin. This is a departure from earlier microarchitectures such as {{\\|ZhangJiang}} which were a lightly modified version of [[VIA Technologies]] ([[Centaur Technology|Centaur]]) architecture. WuDaoKou is a new and complete [[SoC]] design. Whereas prior processors had separate [[dies]] connected together over the legacy [[front-side bus]], the new design is a single-die [[system-on-a-chip]] design that features [[8 cores|8]] integrated [[x86]] cores consisting of two clusters of four cores each connected over a new point-to-point crossbar, improving the internal bandwidth and latency considerably. The new chip also integrated the memory controller and the rest of the [[north-bridge]] on-die as well which further improved latency, bandwidth, and performance. The new chip also has an [[integrated graphics processor]] supporting 4K resolution and up to three screens via an array of display ports.

Overall, [[Zhaoxin]] has reported the new microarchitecture to have 25% improvement in [[IPC]], 140% improvement in multi-core workloads, and 120% higher memory access bandwidth.

=== Uncore ===
WuDaoKou features a new point-to-point high-speed interconnect [[crossbar]] which replaces the [[front-side bus]] from prior architectures. The new crossbar reduces the latency and provides facilities for control flow and cache coherency. Going through the crossbar is also the newly integrated graphics processor as well the memory controller. The new memory controller now supports up to dual-channel [[DDR4]] with data rates of up to 2400 MT/s (although current SKUs only seem to support up to 2133 MT/s). [[Zhaoxin]] has stated that this is the first domestic CPU to have a dual-channel DDR4 memory controller.

== Core ==
=== Pipeline ===
WuDaoKou features an 18-stage pipeline with a 15 cycle misprediction penalty.
:[[File:wudaokou pipeline.svg|800px]]

== Graphics ==
The exact architecture of the [[GPU]] has not been disclosed but there is some evidence that suggest they may be using a [[S3 Graphics]] IP (originally owned by [[VIA Technologies]] as well but has since been purchased by HTC.) The GPU supports up to three displays using [[HDMI]] 1.4b, [[DisplayPort]] 1.2a, [[Embedded DisplayPort]] 1.3, and [[VGA]]. The GPU supports DirectX 11.1 and up to [[4K]] resolution.

== Sockets/Platform ==
[[File:zhaoxin zx-200 chipset.png|right|200px]]
All parts use a HFCBGA 37.5×37.5 mm package and are effectively a [[system on a chip]]. However, for the most part, those parts get paired with a chipset which serves as an I/O extension chip. The chipset communicates with the microprocessor over standard PCIe 3.0 x4 lanes.

{| class="wikitable" 
|-
! colspan="11" | Chipset
|-
! rowspan="2" | Chipset !! rowspan="2" | TDP !! colspan="2" | PCIe || SATA || colspan="3" | USB || rowspan="2" | Network || rowspan="2" | Process || rowspan="2" | Package
|-
! 2.0 !! 3.0 || 3.0 || 2.0 || 3.1 Gen 1 || 3.1 Gen 2 
|-
| ZX-200 || 6 W || 9 lanes || - || 4 || 6 || 3 || 2 || 10/100M/1 Gbps || [[40 nm]] || FCBGA (21mm x 21mm)
|}

[[File:zx-200 slide.png|400px]]

{{clear}}

== Die ==
[[File:wudaokou floorplan at conference.png|right|250px]]

=== Core module ===
: [[File:wudaokou core.png|500px]]


: [[File:wudaokou core (annotated).png|500px]]

=== Octa-core die ===
* [[HLMC]] [[28 nm process]]
*  187 mm² die size
* 2,100,000,000 transistors

: [[File:wudaokou die shot.png|class=wikichip_ogimage|650px]]


: [[File:wudaokou die shot (annotated).png|650px]]

== All WuDaoKou Processors ==
<!-- NOTE: 
           This table is generated automatically from the data in the actual articles.
           If a microprocessor is missing from the list, an appropriate article for it needs to be
           created and tagged accordingly.

           Missing a chip? please dump its name here: https://en.wikichip.org/wiki/WikiChip:wanted_chips
-->
{{comp table start}}
<table class="comptable sortable tc4 tc8">
{{comp table header|main|7:List of WuDaoKou-based Processors}}
{{comp table header|main|7:Main processor}}
{{comp table header|cols|Family|Launched|Cores|L2|%Frequency|Max Memory|ECC}}
{{#ask: [[Category:microprocessor models by zhaoxin]] [[microarchitecture::WuDaoKou]]
 |?full page name
 |?model number
 |?family
 |?first launched
 |?core count
 |?l2$ size
 |?base frequency#GHz
 |?max memory#GiB
 |?has ecc memory support
 |format=template
 |template=proc table 3
 |userparam=9:9
 |mainlabel=-
}}
{{comp table count|ask=[[Category:microprocessor models by zhaoxin]] [[microarchitecture::WuDaoKou]]}}
</table>
{{comp table end}}

== Documents ==
* [[:File:wudaokou.pdf|WuDaoKou]]

== References ==
* Information was obtained directly from Zhaoxin
* [https://fuse.wikichip.org/news/733/zhaoxin-launches-their-highest-performance-chinese-x86-chips/ Zhaoxin launches their highest-performance Chinese x86 chips]
codename	WuDaoKou +
core count	2 +, 4 + and 8 +
designer	Zhaoxin +
first launched	December 28, 2017 +
full page name	zhaoxin/microarchitectures/wudaokou +
instance of	microarchitecture +
instruction set architecture	x86-64 +
manufacturer	HLMC + and SMIC +
microarchitecture type	CPU +
name	WuDaoKou +
pipeline stages	18 +
process	28 nm (0.028 μm, 2.8e-5 mm) +