jit

How would a DOM-less,statically typed, ahead-of-time-compiled javascript code compare to native code performance-wise?

≯℡__Kan透↙ 提交于 2019-12-04 12:49:34
The traditional answer to "why is Javascript slower than native code?" is: "Because it's interpreted". The problem with this claim is that interpretation is not a quality of the language itself. As a matter of fact, nowadays most Javascript code is being JITed, still, this isn't even close to native speed. What if we remove the interpretation factor from the equation and make Javascript AOT compiled? Will it then match the performance of native code? If yes, why isn't this widely done over the web*? If no, where is the performance bottleneck now? If the new bottleneck is DOM, what if we

Hotspot JIT optimization and “de-optimization”: how to force FASTEST?

若如初见. 提交于 2019-12-04 12:44:20
I have a BIG application that I'm trying to optimize. to do so, I'm profiling / benchmarking small elements of it by running them millions of times in a loop, and checking their processing time. obviously Hotspot's JIT is kicking in, and I can actually see when that happens. I like it, I can clearly see things going much faster after the "warm up" period. however, after reaching the fastest execution speed and keeping it for some time, I can see that the speed is then reduced to a less impressive one, and it stays there. what's executed in the loop does not actually change much, so I can

Is IL generated by expression trees optimized?

帅比萌擦擦* 提交于 2019-12-04 11:41:24
问题 Ok this is merely curiosity, serves no real world help. I know that with expression trees you can generate MSIL on the fly just like the regular C# compiler does. Since compiler can decide optimizations, I'm tempted to ask what is the case with IL generated during Expression.Compile() . Basically two questions: Since at compile time the compiler can produce different (may be slightly) IL in debug mode and release mode , is there ever a difference in the IL generated by compiling an expression

Are static methods eagerly compiled (JIT'ed)?

走远了吗. 提交于 2019-12-04 11:19:00
问题 Per my understanding, both instance methods and static methods are treated same by CLR compiler and the IL code is JITted whenever the method is called first time. Today I had a discussion with my colleague and he told me that the static methods are not treated the same way as instance methods. i.e. Static methods are JITted as soon as the assembly is loaded into application domain whereas instance methods are JITted as they are called for the first time. I am actually confused and do not see

Suppress JIT optimization on module load (managed only)

北战南征 提交于 2019-12-04 10:41:42
问题 If I run a release build in VS but WITH debugger attached. So I can set breakpoints and investigate the optimized code disassembly. Usually, in order to see all optimizations I need to run WITHOUT a debugger attached and detach to the running proccess. Does unselecting the "Suppress JIT optimization on module load (managed only)" switch in Visual Studio is sufficient to bring the same result? By 'same result' I mean: same (optimized) machine instructions as by starting without debugger

Numba: calling jit with explicit signature using arguments with default values

孤街醉人 提交于 2019-12-04 10:15:36
I'm using numba to make some functions containing cycles on numpy arrays. Everything is fine and dandy, I can use jit and I learned how to define the signature. Now I tried using jit on a function with optional arguments, e.g.: from numba import jit import numpy as np @jit(['float64(float64, float64)', 'float64(float64, optional(float))']) def fun(a, b=3): return a + b This works, but if instead of optional(float) I use optional(float64) it doesn't (same thing with int or int64 ). I lost 1 hour trying to figure this syntax out (actually, a friend of mine found this solution by chance because

JVM Compile Time vs Code Cache

Deadly 提交于 2019-12-04 09:46:58
I've been benchmarking my app and analyzing it with JMC. I've noticed that under load, it performs quite a bit of JIT compiling. If I send a large amount of transactions per second, the compile time spikes. The compile time always grows proportionally with any heavy load test against the app. I've also observed that the Code Cache slowly rises as well. So I decided to raise the Code Cache reserve to 500MB to test. Bad move! Now it's spending even more time performing JIT. Then I explicitly disabled code cache flushing via -XX:-UseCodeCacheFlushing . However, I noticed that the peak Code Cache

if javascript interpreter does “JIT compilation”, does it cache results of it for use on the same script next time I load the website?

北城以北 提交于 2019-12-04 09:14:27
问题 to make it more specific, I mostly care about SpiderMonkey interpreter in Firefox. So suppose I want to speed up the loading of a particular website in my browser or else speed up loading of all websites that have some popular script, e.g. JQuery. Presumably the scripts involved don't change between the page reloads. Will SeaMonkey understand that much and avoid full recompilation? If SpiderMonkey wouldn't, will any other interpreter? Or is this basically a potential new feature which nobody

RyuJit producing incorrect results

戏子无情 提交于 2019-12-04 09:07:25
问题 After recently upgrading to .net 4.6 we discovered a bug where RyuJit produces incorrect results, we were able to work around the issue for now by adding useLegacyJit enabled="true" to the app.config. How can I debug the machine code generated by the following? I created a new console project in VS 2015 RTM, set to Release, Any CPU, unchecked Prefer 32 bit, running with and without debugger attached produces the same result. using System; using System.Runtime.CompilerServices; namespace

Disabling JIT in Safari 6 to workaround severe Javascript JIT bugs

邮差的信 提交于 2019-12-04 08:59:10
问题 We found a severe problem with the interpretation of our Javascript code that only occurs on iOS 5/Safari 6 (then current iPad release) that we think is due to critical bug in the Just in Time JS compiler in Safari. (See updates below for more affected versions and versions that seem to now contain a fix). We originally found the issue in our online demos of our library: the demos crash more or less randomly but this happens only the second time (or even later) that the same code is executed.