Qichang's Blog - SPO600

In our final project, the project will split into 3 stages. This is the first stage of my SPO600 course project. In this stage, we are given a task to find an open source software package that includes a CPU-intensive function or method that compiles to machine code. After I chose the open source software package, I will have to benchmark the performance of the software function on an AArach64 system. When the benchmark job is completed, I will have to think about my strategy that attempts to optimize the hash function for better performance on an AArch64 system and identify it, because those strategies will be used in the second stage of the project. With so many software, I would say picking software is the hardest job in the project, which is the major reason it took me so long to get this post going. But after a lot of research, I picked a software called SSDUP , it is a traffic-aware SSD burst buffer for HPC systems. You can find the source code over here: https://github.com/CGC

This lab is separated into two parts, I'll blog my work in different post. In the first part, we've got a source code from professor Chris, which is a similar stuff to our lab5, scaling the volume of sound, but it includes inline assembler. The first thing I'll do is add a timer to the code in order to check the performing time. Build and run the program, here is the output: ------------------------------------------------------------------------- [qichang@aarchie spo600_20181_inline_assembler_lab]$ ./vol_simd Generating sample data. Scaling samples. Summing samples. Result: -462 Time: 0.024963 seconds. ------------------------------------------------------------------------- Then I adjusted the number of samples to 5000000 in vol.h: ------------------------------------------------------------------------- [qichang@aarchie spo600_20181_inline_assembler_lab]$ cat vol_simd.c // vol_simd.c :: volume scaling in C using AArch64 SIMD // Chris Tyler 2017.11.29-2018

In this lab, we are going to use different approaches to scale volume of sound, and the algorithm’s effect on system performance. Here is some basic knowledge of digital sound: Digital sound is usually represented by a signed 16-bit integer signal sample, taken at a rate of around 44.1 or 48 thousand samples per second for one stream of samples for the left and right stereo channels. In order to change the volume of sound, we will have to scale the volume factor for each sample, the range of 0.00 to 1.00 (silence to full volume). Here is the source code I got from professor: (vol1.h) ------------------------------------------------- #include <stdlib.h> #include <stdio.h> #include <stdint.h> #include "vol.h" // Function to scale a sound sample using a volume_factor // in the range of 0.00 to 1.00. static inline int16_t scale_sample(int16_t sample, float volume_factor) { return (int16_t) (volume_factor * (float) sample); } int main() { // Al