Programmers agonize over whether to allocate on the stack or on the heap.
Some people think garbage collection will never be as efficient as direct memory management, and others feel it is easier to clean up a mess in one big batch than to pick up individual pieces of dust throughout the day. This article pokes some holes in the oft-repeated performance myth of slow allocation in JVMs.
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Member since:2005-07-06
Member since:2005-10-08
"Yes, Java is so fast that it can outperform C++ only in controlled lab environments. Yeah right, welcome to the real world!"
Yes. I will tell you about the real world. In the real world, Java is mostly used for server applications that do 100% duty cycle, where startup time is not important, and where the JIT can work its magic. In the real world, these types of applications are horribly unsuited to C++, and are also dangerous to write in C++. In the real world, speed of development and security are usually more important than squeezing out a slight improvement in performance, even if such an improvement is possible. C++ has neither speed of development, or security. In the real world other common options for server side application development, such as Perl, are 10 to 15 times slower than Java. PHP fairs even worse than Perl when it comes to performance.
"Not only the benchmarks speak, the real world examples speak as well. Java is at this time no performance match for any traditional compiled language."
Incorrect. For most common operations, there is virtually no speed difference these days beween that operation performed in C++ and that operation performed in Java, once the JIT has been allowed to work its magic. Again, the main problem right now is that JIT optmizations are not persistant across program executions. This is detrimental on the desktop, but of no consequence on servers. However, that will be changing as well, Persistant JIT optimizations are on Sun's to do list.
Member since:I only read claims about the shootout being useless but no arguments. At least it is an open benchmark and everyone is free to discuss its shortcomings on public mailing lists. You can submit solutions if you think the present ones are not optimal.
Anyway, the shootout results do not seem to be that unrealistic. Show me the (unflawed) benchmarks that indicate that Java could be faster than C++. I find it somewhat reveiling that from the perspective of the Java zealots every benchmark that does not select Java as the performance king is discredited. They ignore empirical results as well as the public perception. What is the name of the reality distortion field you are living in?
Member since:2005-10-08
"Anyway, the shootout results do not seem to be that unrealistic. Show me the (unflawed) benchmarks that indicate that Java could be faster than C++."
http://www.kano.net/javabench/
The author indicates which tests he used, what operating system he performed the tests on, and what optimization settings he used for both GCC and Java. Java outperformed GCC in many of the cases.
Another study showed that on a standard bubble short, Java outperforms GCC even when GCC has all optimizations turned on.
In their paper "Benchmarking Java against C and Fortran for Scientific Applications", J.M. Bull, et al. from the Edinburgh Parallel Computing Center found that Java performance was always within 20% of the same algorithims written in C or FORTRAN. The authors concluded that "On Intel Pentium hardware, especially with Linux, the performance gap is small enough to be of little or no concern to programmers." In this same test, Java actually outpeformed some C compilers.
So now tell me again that I am ignoring empirical results. You call me a Java zealot, but it sounds more to me like you are one of the Java haters, who will accept the results of any benchmark, no matter how flawed that benchmark is, to support your assertion that Java is slower than C++.
Member since:2005-07-06
I concluded that the shootout was useless the minute I downloaded some of the Dylan benchmarks, and realized that my results were nothing like the ones published on the site. Apparently (at least in earlier versions of the shootout), the data set for the benchmarks was so small that the C versions would complete in like 0.01 seconds, while the Dylan version would take like 0.1 seconds. When I jacked up the number of iterations, the two versions performed very similarly. I traced the issue to the fact that the Dylan runtime took a fixed amount of time during program startup, which meant that the Dylan program didn't even get started by the time the C program had exited. Yet, does the user really care about a 0.1 second startup cost? Or is the user more concerned about performance with large data sets?
Beyond that, its fundamentally flawed to compare performance on a given benchmark when the various implementations are written by different authors. It's the opposite of the scientific method --- you change only one variable at a time! The fact that the Shootout has a lot of different benchmarks doesn't make up for that basic flaw. A shitty experiment repeated dozens of times is still a shitty experiment!
In my own experiments (I've been meaning to get around to doing a proper Lisp vs. Scheme vs. Dylan vs. C++ benchmark), I've written a version of Fannkuch (one of the benchmarks on the shootout site) that was as fast in Bigloo Scheme as in C++. Meanwhile, the shootout says that Scheme is 1/6 the speed in Fannkuch as C++. Whose conclusion am I going to trust?
"Microsoft has sensationally abandoned its controversial plans to restrict the sharing of XBox One games, and has also removed daily online authentication requirements for its forthcoming console", reports The Guardian. They had no choice. Still a good move."A snippet of code in the Steam digital distribution platform has revealed that Valve may be planning to let users easily share their games with friends in the future. The Verge has verified the code's authenticity, which was originally spotted by a member of the NeoGAF gaming forum; the code references a 'shared game library' and a notification that would alert a user when their games are currently in use by a borrower." This would change the, uh, game.
Official Apple statement on PRISM and privacy: "Regardless of the circumstances, our Legal team conducts an evaluation of each request and, only if appropriate, we retrieve and deliver the narrowest possible set of information to the authorities. In fact, from time to time when we see inconsistencies or inaccuracies in a request, we will refuse to fulfill it." This is basically Apple re-publishing their earlier statement in a more official manner. You either believe it, or you don't.
The open source Contiki operating system and its commercial Thingsquare distribution are making strides towards the connected home. According to a Computerworld article, a new LED light bulb manufacturer is putting small computers into their light bulbs. Each computer runs the Contiki OS, which gives each bulb an IP address and allows them to be controlled with a smartphone application. To connect the bulbs to the application, the bulbs use both Wi-Fi and the much lower power IEEE 802.15.4 mesh technology.
"Google asked the secretive Foreign Intelligence Surveillance Court on Tuesday to ease long-standing gag orders over data requests it makes, arguing that the company has a constitutional right to speak about information it's forced to give the government. The legal filing, which cites the First Amendment's guarantee of free speech, is the latest move by the California-based tech giant to protect its reputation in the aftermath of news reports about sweeping National Security Agency surveillance of Internet traffic." Draining the ditch after the cow has drowned in it."I can't find one person who has been using the Nexus 7 for an extended period of time, and hasn't seen a massive downgrade in performance. Just what kind of downgrade are we talking here? I cannot pick up my Nexus 7 without experiencing problems like a lag of ten seconds, or more, just to rotate the display; touches refusing to acknowledged; stuttering notification panel actions; and unresponsive apps." Fully and utterly agreed. My Nexus 7 was blazing-fast and awesome for a few months, and at some point, it just started sucking. Just like that. I've tried loads of ROMs, and nothing helps.A new release of the hobby operating system MenuetOS! The release notes are a bit non-descript, but you'll have to take what you can get: "updates and improvements (picview, httpc, ehci, ...)"."The Internet is one of the most transformative technologies of our lifetimes. But for 2 out of every 3 people on earth, a fast, affordable Internet connection is still out of reach. And this is far from being a solved problem. There are many terrestrial challenges to Internet connectivity - jungles, archipelagos, mountains. There are also major cost challenges. Right now, for example, in most of the countries in the southern hemisphere, the cost of an Internet connection is more than a month's income. Solving these problems isn't simply a question of time: it requires looking at the problem of access from new angles. So today we're unveiling our latest moonshot from Google[x]: balloon-powered Internet access." Insane."MineAssemble is a tiny bootable Minecraft clone written partly in x86 assembly. I made it first and foremost because a university assignment required me to implement a game in assembly for a computer systems course. Because I had never implemented anything more complex than a 'Hello World' bootloader before, I decided I wanted to learn about writing my own kernel code at the same time. Note that the goal of this project was not to write highly efficient hand-optimized assembly code, but rather to have fun and write code that balances readability and speed. This is primarily accomplished by proper commenting and consistent code structuring." Just cool.
Jon Rubinstein, former CEO of Palm: "Well, I'm not sure I would have sold the company to HP. That's for sure. Talk about a waste. Not that I had any choice because when you sell a company you don't get to decide that. Obviously, the board and shareholders decide that. If we had known they were just going to shut it down and never really give it a chance to flourish, what would have been the point of selling the company? I think the deal we had with Verizon really hurt us, but who knew that at the time? These things are all hindsight."
Member since:
2005-10-08
Yeah, as others have pointed out, this link is worthless. The benchmarks are not even remotely accurate.
More controlled benchmarks have conclusively shown that in some cases, Java can outperform C++ because of the runtime optimization. As I said in another reply, Java can perform dynamic optimizations on code that C++ cannot even dream about since it is limited to only static optimizations at compile time.