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diff --git a/docs/paper.tex b/docs/paper.tex index 89503442..87aebe30 100644 --- a/docs/paper.tex +++ b/docs/paper.tex @@ -602,18 +602,51 @@ explicitly available to Emscripten. \subsection{Benchmarks} +We will now take a look at some performance benchmarks: + +\bigskip + \begin{tabular}{ l | c | c | c } + \hline \textbf{benchmark} & \textbf{JS} & \textbf{gcc} & \textbf{ratio} \\ - raytrace (5, 64) & 1.553 & 0.033 & 46.45 \\ - fannkuch (9) & 0.663 & 0.054 & 12.27 \\ - fasta (100,000) & 0.578 & 0.055 & 10.51 \\ + fannkuch (9) & 0.577 & 0.054 & 10.68 \\ + fasta (100,000) & 0.640 & 0.055 & 11.63 \\ + primes & 0.490 & 0.160 & 3.06 \\ + raytrace (5, 64) & 1.078 & 0.033 & 32.66 \\ + \hline \end{tabular} \bigskip -LLVM opts, closure -SM -m -gcc -O3 +The first column is the name of the benchmark, and in parentheses any +parameters used in running it. The source code to all the benchmarks +can be found at \url{https://github.com/kripken/emscripten/tree/master/tests} +(each in a separate file with its name, except for `primes', which is +embedded inside runner.py in the function test\_primes). The second +column is of running the compiled code (using all Emscripten and LLVM +optimizations, as well as the closure compiler) in the SpiderMonkey JavaScript +engine (specifically, the JaegerMonkey branch, running with \emph{-m -n -a}). +The third column is the results when compiling the original code with \emph{gcc -O3}. +The last column is the ratio, that is, how much slower the JavaScript code is +when compared to gcc. + +Clearly the results very wildly by the benchmark, from 3.06 to 32.66 times +slower. It appears that code that does simple numerical operations -- like +the primes test -- can run fairly fast, while code that has a lot of memory +accesses, for example due to using structures -- like the raytrace test -- +will be much slower. (The main issue with structures is that Emscripten does not +`nativize' them yet, as it does to simple local variables. Improving Emscripten to +do so is possible, +but would take a significant amount of work.) + +For code that has a mix of simple numerical operations and memory accesses, +it tends to run around 10 times slower than the most-optimized C++ code, +as we can see in the fannkuch and fasta benchmarks. While a factor of 10 +is a significant slowdown, it is still more than fast enough for +many purposes, and the main point of course is that the code can run +anywhere the web can be accessed. Further work on Emscripten is expected to +improve the speed as well, as are improvements to LLVM and the Closure +Compiler. \section{Emscripten's Architecture} @@ -870,7 +903,14 @@ construction to more natural JavaScript code flow structures.) Emscripten has been run successfully on several real-world codebases, including the following: \begin{itemize} -\item \textbf{CPython} +\item \textbf{Python}. It is possible to run variants of Python on +the web in various ways, including pyjamas, IronPython on SilverLight and +Jython in Java. However, all of these are slightly nonstandard in the +the Python code they run, while the latter two also require plugins to be +installed. With Emscripten, on the other hand, it is possible to compile +CPython itself -- the standard, reference implementation of Python -- and +run that on the web, which allows running standard Python code. An online +demo is available at \url{http://syntensity.com/static/python.html}. \item \textbf{Poppler and FreeType} \item \textbf{zlib} \item \textbf{Bullet} |