嵌入式異質多核心虛擬平台之設計

Designing Virtual Platforms for Embedded Heterogeneous Multicore Systems

蔡東杰(Tung-Chieh Tsai)

指導教授 ： 洪士灝

國立臺灣大學/電機資訊學院/資訊工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.10464

摘要

在嵌入式異質多核心(embedded heterogeneous multicore)平台上開發軟體往
往相當複雜,難以為程式除錯以及監控和分析程式的行為。相較於在真實硬體上
開發與分析軟體,全系統模擬(system-level simulation)提供了另一個選擇。
在足夠的模擬速度和準確性下,全系統模擬可以有效幫助軟體開發、分析,與散
布。然而,一個模擬器要同時提供快速的模擬與高準確性是非常困難的,因為這
兩項目標是是互相矛盾的。所以我們認為一個好的模擬環境不僅要利用各種技術
來提高兩者,同時亦須在此之中找到一個平衡點。此外,為了幫助軟體開發,並
有效利用系統模擬環境的額外功能,模擬器之上必須支援一個整合的軟體開發環
境。
在本論文中,我們提出了一個架構,可以將既有的模擬器作為基礎,建立異
質多核心的虛擬平台,並且開發出一套多核心開發板支援套裝軟體(multicore
board support package)來幫助虛擬與真實平台的軟體開發。在模擬器的設計
上,我們利用多核心主機加速應用程式及系統程式執行,有效解決多核心平台模
擬速度不足的問題。為了驗證這個架構的可行性與實用性,我們使用一個嵌入式
異質多核心平台PAC Duo SoC 作為範例研究。
在範例研究中,我們在 PAC Duo SoC 實際硬體支援準備好之前就開始在虛擬
平台上進行工作,以降低未來的軟體移植成本和提前開發時程,並協助應用程式
的開發與分析。實驗結果顯示,我們虛擬平台可以用比實際硬體快的速度來開起
作業系統;在對資料處理器做詳細的模擬時可以到達到每秒一到兩百萬個指令。
我們的系統在資料平行的程式上,可以利用多核心主機模擬多核心系統以達到線
性加速,顯示出我們的架構具有極佳的的擴充性。

關鍵字

虛擬平台 ； 系統模擬 ； 嵌入式系統 ； 多核心 ； 效能分析

並列摘要

Developing software on an embedded heterogeneous multicore platform is complicated,
since it is relatively hard to debug programs and monitor the performance
of the programs running on the actual system. In contrast, full system simulation
is also a viable approach, but simulation speed and timing accuracy would be the
two important issues which may need to balanced to satisfy the requirements from
the user. Furthermore, to support software development on a multicore platform
with proper modeling of the simulated hardware within a simulator, an integrated
software stacks should also be provided.
In this thesis, we propose a framework for constructing multicore virtual platforms
from single-core simulators, with a set of multicore board support packages
for multicore software development. To speed up the execution of complex applications
and system software, we developed techniques to perform multicore simulation
on a multicore host. To verify the usefulness of the proposed framework, we
implemented a virtual platform for an embedded heterogeneous multicore platform, PAC
Duo SoC, as an case study.
In our case study, we started developing system software for the PAC Duo SoC
before the evaluation board and official board support package are ready, which
greatly reduced our porting efforts and shortened the time for us to develop system
software for the system. Our results showed that our virtual platform was able boot
operating system faster than the real platform with a fast functional emulation
mode. The speed of our virtual platform was still quite fast, operating at 1 to 2
MIPS, when a detailed simulation mode was used. When running on a multicore
host, the virtual platform exhibits near-linear speedups for data paralleled programs
and indicates high scalability with good accuracy under our framework.

並列關鍵字

virtual platform ； full system emulation ； embedded system ； multicore ； performance analysys

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