Assuming a typical 650mW power budget for DRAM access, an application can only sustainably use a total of 100MB per frame at 60FPS. Optimizations that help to minimize GPU memory bandwidth consumption are a high priority for mobile application development. 在通常情况下,GPU对DRAM的访问,每1GB/s...
参考MegEngine/MegPeak的代码以及MegPeak分析,在A76上测试了一下fmla、sdot指令延迟: A76:2419200kHz #define CLEAR(i) "eor v" #i ".16b, v" #i ".16b, v" #i ".16b\n" // #define TEST_ASM(i) "fmla v" #i ".4s, v" #i ".4s, v" #i ".4s\n" #define TEST_ASM(i) "fmla ...
由于Arm能够将dispatch stages从2个周期减少到1个周期，因此新的核心总体上将其pipeline长度从11个周期减少到10个周期。需要注意的是，我们必须将pipeline cycles与mispredict penalties分开来，在大多数情况下，后者在Cortex-A77设计中已减少到10个周期。移除pipeline stage通常是一个相当大的变化，特别是考虑到Arm的目标...
In the execution core, the Cortex-A76 boasts two simple arithmetic locus units (ALUs) for basic math and bit-shifting, one multi-cycle integer and combined simple ALU to perform multiplication, and a branch unit. The Cortex-A75 just had one basic ALU and one ALU/MAC, which helps explain ...
Highlights of Cortex A76: Architecture – Armv8-A (Harvard) with Armv8.1, Armv8.2, Armv8.3 (LDAPR instructions only), cryptography and RAS extensions ISA support – A64; A32 and T32 (at the EL0 only) Microarchitecture Pipeline – Out-of-order ...
现在，A78能够同时解析每个周期的两个预测，从而极大地增加了核心这一部分的吞吐量，并且能够更好地从分支预测错误以及核心下游进一步产生的 pipeline bubbles中恢复过来。Arm声称他们的微体系结构是非常受分支预测驱动的，因此此处的改进大大增加了内核的世代改进。自然，分支预测器本身在准确性方面也得到了改进，这是每...
separately. This allows the predictor to prime the core's caches way ahead of actual execution time with code that it reckons will be executed, and minimize bubbles in the pipeline during which the core can't do anything useful. Overall, this split method gives the A76 a lift over its ...
就新A510的前端而言,我们看到了一个128位的fetch pipeline ,这意味着它每个周期最多可以获取4条指令,这给前端留出了一些余地来关闭分支气泡。解码器的实际宽度已从2宽增加到3宽。 在分支预测方面,一如既往Arm并未透露太多细节,但该公司确实指出,它在大型核上使用了相同的最新方法和技术。L1指令高速缓存可以是32KB...
fed and prevent pipeline stalls. The introduction of a macro-op cache should also reduce the effective latency of a branch prediction miss from 11 cycles down to 10, even though the CPU technically has a 13-stage pipeline. The decoder width is also increased, to 6-wide, up from 4-wide....
shaving off a cycle of the effective pipeline depth of the core. What this means is that the core’s branch mispredicts latency has been reduced from 11 cycles down to 10 cycles, even though it has the frequency capability of a 13 cycle design (+1 decode, +1 branch/fetch overlap, +1...