Skip to main content

Final Project Part 01 - Benchmarking and how to Optimize the Sha1 Function in clib

To benchmark the sha1test file I copied the flags from the standard make file of clib and placed it in the local dev makefile of sha1. It yielded the following results after I used clock to time the functions in each test:



The revised timing code can be found here for personal testing. Now we can see the majority of the time is spent in Test 6, so we are going to apply our optimization and hopefully see a change in the speed of that test. The current cflags of the standard clib Makefile are as follows:

-DCURL_STATICLIB -std=c99 -Ideps -Wall -Wno-unused-function -U__STRICT_ANSI__ $(shell deps/curl/bin/curl-config --cflags)

I plan on adding the -O3 optimization here. The challenge will be to either ensure that this does not affect any other dependancy or I will have to make a special case in the Makefile for only the SHA1 function.

I also plan to take out the if condition below in the sha1.c file and putting the if case in another loop.

 
 This appears to be the only optimizations I can currently make due to the uniqueness of the sha1 implementation, if more are determined they will be applied.

Comments

Post a Comment

Popular posts from this blog

Final Project Part 02 - Sha1 Function Enhancements

To try to squeeze out a bit more performance I attempted to some compiler optimizations. Unfortunately, due to the sheer complexity of the algorithm, I was unable to find other logic complexities to simplify. I tried some loop unrolling to make the compiler have to work a little less, some examples are here below: I made a graph to demonstrate the minute differences this makes in the test vectors below: At most a few millisecond difference is all that can be acquired, and this is only from the finalcount[] array as the digest array produces errors if not compiled in a loop along with other for loops in the code. To test this I simply altered the sha1.c code and ran the make file to see if the vectors passed or failed. As mentioned this is a compiler optimzation, in other words it is completed already, especially at the -O3 level where the benchmarking was done. I would not  recommend this change to be pushed upstream normally due to the insignificant time ch...
Post a Comment
Read more

Final Project Part 01 - Final Summary

To end part 1 I will summarize what information I have gathered for part 2: I am optimizing clib, a package manager. After benchmarking, it is clear there is a significant time delay in some advanced calls of the SHA1 function, such as ones that call update many times. To optimize, I am going to add the -O3 flag and remove a loop condition (currently). Some other observations: This project is relatively small with no ./configure for other platforms. The Sha1 code is unique and does not conform to the simple sha1 algorithm such as on    Wikipedia . The documentation (i.e. README) is relatively vague at describing the dependancies. It suggests only syntax that implies installation and isn't clear at documenting development vs. published code.   I have learned alot getting to this point in part 1. Firstly, I learned that library files can only be linked by using sudo ldconfig and the files must be in usr/lib. Secondly, I learned how to alter an advance...
Post a Comment
Read more

Loops in Assembly Architectures (Lab 3)

The modern C and C++ languages are often taken for granted for their simple syntax and compiler intuition. In Assembly, every variable and value are stored in registers, simple output lines are multiple statements in length, and a number can only be 0 to 9. Below I examine two different architectures, X86_64 and aarch64: x86_64 The loop I have created that outputs Loop: number thirty times can be found here . Writing this was extremely difficult, constantly fighting a lack of good documentation and examples online. To write this code I viewed many examples online, wrote pseudo code, and wrote the program in C++ before beginning. Debugging was difficult as the errors given were vague or rididculous at times (no // style commenting comes to mind). The Visual Studio compiler for writing C or C++ for example, is alternatively much more informative and allows for easy: break points, live variable information, and detailed information on error codes. I dislike X86 for the limited amou...
Post a Comment
Read more