|Process||28 nm, 16 nm|
|L1I Cache||128 KiB/core|
4-way set associative
|L1D Cache||64 KiB/core|
4-way set associative
|L2 Cache||2 MiB/cluster|
16-way set associative
Denver is a CPU microarchitecture from Nvidia introduced in 2014, capable of executing ARMv8 code natively and with help of dynamic code optimization. Native ARM decoder can issue up to 2 instructions per cycle, and up to 7 micro-operations are started per cycle when dynamic code translation is used.
Denver is 7-wide in-order superscalar. It has ARMv8 hardware decoder (A32, T32, and A64 modes) which can generate up to 2 micro-ops per cycle. Also it can execute up to 7 micro-ops per-cycle directly from L1i cache. Denver has 7 execution units: 1 branch, 2 integer (1 has hardware multiply module), 2 FP/NEON (128-bit), 2 Load/Store units.
Denver 2 has dynamic branch prediction with Branch Target Buffer and Global History Buffer (Conditional Direction Predictor - gshare-agree). It also has Return Stack Buffer, Indirect Target Predictor and static predictor.
Pipeline of Denver 1 has 15 stages, mispredict penalty is 13 cycles.
|Stage action:||ITLB||I$ Rd||Way Sel||Decode||Fetch Q||Pick||Sched||RF Rd||Bypass||Ld Addr||D$ Read||Bypass||ALU/Execute||St Addr||RF wr|
Dynamic Code Optimization
For often executed code optimization micro-interrupt can be generated and firmware-based optimizer is started. Using "Dynamic Profile Information" optimizer can translate ARMv8 instructions into optimized microcode sequence and save it into Optimization Cache. Then Denver will execute code directly from Optimization Cache (part of 128 MiB microcode carve-out) without using hardware ARMv8 decoder. Several microcode sequences may be chained.
In 2014 Nvidia listed several optimizations for the dynamic code translation:
- Unrolls Loops
- Renames registers
- Reorders Loads and Stores
- Improves control flow
- Removes unused computation
- Hoists redundant computation
- Sinks uncommonly executed computation
- Improves scheduling
For two cores of Denver total cache size is:
L1i TLB has 128 entries for 4 KiB pages and is 4-way set-associative. L1d TLB has 280 entries and supports 4 KiB, 64 KiB, 1 MiB and 2 MiB pages. TLB walk is accelerated by L2 TLB of 2048 entries in 4-way set-associative buffer.
Denver is used in Nvidia's Tegra K1-64 (2014, 28 nm, model T132). It is used in Google's Nexus 9 tablet, produced by HTC.
Denver 2 is used in Nvidia's Tegra X2 "Parker" (2016, 16 nm, model T186). Parker SoC has 4 Cortex-A57 cores and two Denver-2 cores. It is used in Nvidia Drive PX2 and Nvidia Jetson TX2.
All Denver Chips
|List of all Denver Chips|
|core count||2 +|
|first launched||2014 +|
|full page name||nvidia/microarchitectures/denver +|
|instance of||microarchitecture +|
|instruction set architecture||ARMv8 +|
|l1$ size||0.375 MiB (384 KiB, 393,216 B, 3.662109e-4 GiB) +|
|l1d$ description||4-way set associative +|
|l1d$ size||0.125 MiB (128 KiB, 131,072 B, 1.220703e-4 GiB) +|
|l1i$ description||4-way set associative +|
|l1i$ size||0.25 MiB (256 KiB, 262,144 B, 2.441406e-4 GiB) +|
|l2$ description||16-way set associative +|
|l2$ size||2 MiB (2,048 KiB, 2,097,152 B, 0.00195 GiB) +|
|microarchitecture type||CPU +|
|process||28 nm (0.028 μm, 2.8e-5 mm) + and 16 nm (0.016 μm, 1.6e-5 mm) +|