Perl eval performance

Board index » Perl. I seem to remember at some point reading in a book somewhere most likely the Camel that the first use of an eval is pretty inefficient, but subsequent uses are not, because the overhead has already been incurred what overhead? Presumably the overhead of firing up another Perl interpreter. Can anyone verify this? Is there a penalty for more than one use? Presumably the overhead of :firing up another Perl interpreter.

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Content:

• Section 19.8. Benchmarking
• performance
• Zabbix Documentation 5.4
• Обсуждение: Perl DBI, PostgreSQL performance question
• 6 Perl Eval Function Examples – Regex, Error Handling, Require, Timeout, Dynamic Code
• Re: Perl DBI, PostgreSQL performance question
• Pattern Modifiers
• Perl error handling

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Section 19.8. Benchmarking

It's a little bit ridiculous, but you could actually have this if you transpiled perl to rust :. The amount of perl 5 that relies on 'eval', and invoking the interpreter and compiler at runtime in various degrees , is. None of that should be taken as condemning that tendency in Perl. Yeah, the entire thing is rubbish. I'll just keep writing perl5 that solves customers' problems, and use the rust integration we now have to write fast safe code when I need that.

Yeah but then how do you achieve what perl 11 sets out to be then? The only problem with eval is it's internal slow implementation, compared to a proper language. For perl being a 20x slower scripting language it's fine though. Their documentation is full of hype and lies. For proper performance and safeties use pony. ATS is also fine, and there some new parallel languages cropping up. For slow and safety alone there are also many nice copying languages around, like Go, Erlang, Scala, Akka or Lisp.

We have no chance to catch up to javascript, only to php7. But even this is not easy because the perl5 API is as fucked up as the ruby and python API, exposing its bloated inner structs instead of functions only.

You only get proper performance by optimizing those fat structs to single words, "unboxing" data, slimming down the code and runloop. With an exposed API like that based on structs you are doomed to be 10x slower. Additionally there are so many exposed globals in the API, that proper threading is almost impossible.

The goal of gperl was to add proper eval but it's not easy, and he already went away from perl5 to go and java, as most asians did recently. There's spvm though, a new asian perl5 attempt to create a proper VM. The goal of perl11 is simply to add most perl6 features to the perl5 codebase without breaking backcompat. This is what perl5 should have done, but refused to do and is not able to do.

That's from rperl. He added that goal just yesterday :. One beast will rise from the desert, the other from the sea. When they meet, they will fuse to form the prophesied CamelCrab, and you will know the end is nigh. Could you though? I mean the semantics are so different that the code you generate is probably going to need to be the equivalent of Perl's VM at that point anyway.

So, in short, the answer is no. Rust currently lack a clean way to do this. The semantics are hard to translate also. I'm doing a little lang in rust and is HARD. However, is possible? I think you could -- you'd have to just translate all those semantics down to rust as well. Also, if I'm understanding the original post right, they want the VM itself to be swappable -- that with the desire to reach C speed makes me think that they want to make it optional all-together.

Your reasoning is kind of like saying we only need a and a large bank of ram because, hey, that is turing equivalent, and a modern x86 with the same amount of ram is turing equivalent, so it should be complete. Imagine a perl program which asks the user for input. Based on the user's input, the perl program does "do a.

Hell, maybe the user's input is actually executable code that is thrown in the mix too. What should the rust transpiler do? Are they floats? Are they ints? Or strings? Do they have values already? Yes, you could create a transpiled version that used hashes to look up symbols, and based on what the hash returned it would execute code to add two boxed ints, or floats, or float and int, or throw an error, but then what you've done is rewritten the perl interpreter in rust.

Yes, this is literally the case, I didn't say it would be easy or that it should be done. Maybe I should have been more clear, but it was just a silly joke, lighten up.

Any other difficulties you can forsee? Having eval is a part of the language, and without it you aren't transpiling perl, just perl-- or whatever you want to call it. That doesn't make sense, the cost incurred by dynamic languages is not just due to the interpreter otherwise that would be easy to solve with a JIT or, as you point out, static compilation.

Rather the problem is that since these languages are by nature dynamic you can't make many of the assumptions that you do it static languages. You can not know what a value passed as parameter is going to hold until the function is actually called, you cannot inline method calls because they could be redefined dynamically etc For this reason JIT actually makes more sense that static compilation since at least then you'll potentially be able to use dynamic runtime information to better optimize the code.

If untyped the cperl jit will observe run-time types and switch to the unboxed variant or the whole basic block then, if profitable. Same with the object system. A native class has the same layout as a C struct. No costly refcounting and indirections, just a word with the data or pointer. Single op assignments, reads and stores.

Easy to ffi back and forth. Fast objects. You can inline method calls on the tracing jit when it's called often enough with the right types. Static methods can be inlined at compile-time already, but that's not merged yet. A few bits are still missing in the inliner. The static compiler benefits greatly from types also, but the type inference is not that bad also, just a bit unstable B::CC.

Many modules cannot be compiled statically with this optimizing compiler yet. The normal static compiler B::C is stable though and used in production for decades. If you properly type your sigs and vars, the static compiler will fly. If not, the jit has more work to do. The biggest problem is only the non-cooperation from p5p. But this is lame. Or just transpiling into C I don't think you can transpile Perl.

Maybe a subset. RPerl is a Perl 5 transpiler. We started with a low-magic subset of Perl 5, and are now slowly moving into the medium-magic parts of Perl 5 like regular expressions and Moo se and databases etc. Also called the perl-compiler. B::C just jumps into the libperl run-time, but B::CC even tries to optimize away many slow run-time functions, because it knows much more about the code and data.

It's very stable, because I'm maintaining it, and it's used in production. Nor could you with Perl to Rust Hacker News new past comments ask show jobs submit.

performance

Exit Print View. Search Scope:. This Document Entire Library. Documentation Home » Oracle Solaris Language: English. Usually, they must begin with a letter or underscore, in which case they can be arbitrarily long up to an internal limit of characters and may contain letters, digits, underscores, or the special sequence "::" or "'". In this case, the part before the last "::" or "'" is taken to be a package qualifier; see perlmod.

Zabbix Documentation 5.4

Understanding difference s between programming languages is crucial. If wrong language is chosen for a project it will take a lot of time and efforts to change the course and re-implement the project or its part in different language. Typically it takes years of efforts, misery and dissatisfaction for everyone: yourself, your colleagues, your clients and your systems administrator s. Needless to mention it can be dangerous for business. Knowledge of how languages differ from each other is the key to making right decisions. Sometimes it is not easy to answer questions like this, considering many false beliefs and rumors so common among developers. This testing is designed to demonstrate the difference between popular programming languages. I hope you consider results of this little research to be interesting. Test code grows text string by adding another string in cycle until it grows up to 4 mb. Each iteration substitutes some text.

Обсуждение: Perl DBI, PostgreSQL performance question

This year I decided to do something about it. In this post I want to introduce you to Devel::SizeMe, show some screenshots, a screencast of the talk and demo , and outline current issues and plans for future development. Over the next couple of months a few more features were added. The v3 work had involved a complete rewrite of the subroutine profiler and heavy work on much else besides. That project turned into something of an epic adventure with more than its fair share of highs and lows and twists and turns.

6 Perl Eval Function Examples – Regex, Error Handling, Require, Timeout, Dynamic Code

Perl's eval built-in form provides programs with access to Perl's internal parser and evaluator. It may be called with a scalar argument that is, a string or with an expression that evaluates to a scalar argument, or it may be called with a block. The eval built-in has one important role. This role means that eval is critical to proper exception handling. When invoked with a block, the Perl parser compiles the block argument at the same time that it compiles the rest of the code, before it begins execution.

Re: Perl DBI, PostgreSQL performance question

Perl is a family of two high-level , general-purpose , interpreted , dynamic programming languages. Though Perl is not officially an acronym, [11] there are various backronyms in use, including "Practical Extraction and Reporting Language". Raku, which began as a redesign of Perl 5 in , eventually evolved into a separate language. Both languages continue to be developed independently by different development teams and liberally borrow ideas from each other. The Perl languages borrow features from other programming languages including C , shell script sh , AWK , and sed ; [14] They provide text processing facilities without the arbitrary data-length limits of many contemporary Unix command line tools. In addition to CGI, Perl 5 is used for system administration , network programming , finance, bioinformatics , and other applications, such as for GUIs. It has been nicknamed "the Swiss Army chainsaw of scripting languages" because of its flexibility and power, [20] and also its ugliness.

Pattern Modifiers

Inserted new physical disk and used the first partition for the test. The disk for the initial test was on the last partition, separate from the system partition, but on the same physical disk. Result: there is the same cyclic pattern, but the system is no longer unresponsive during the test.

Perl error handling

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The code is compiled at compile time with all other code and eval can use the return statement, so it might be similar overhead like using a sub function. Not that both would have the same function - just as a reference point. Would it be ok, e. Thanks for your wisdom. I might write a bigger benchmark and post the results here.

The current possible PCRE modifiers are listed below. The names in parentheses refer to internal PCRE names for these modifiers. Spaces and newlines are ignored in modifiers, other characters cause error. This is the same as Perl. When this modifier is set, the "start of line" and "end of line" constructs match immediately following or immediately before any newline in the subject string, respectively, as well as at the very start and end.

In this case, the information is sent from an SNMP-enabled device and is collected or "trapped" by Zabbix. Usually, traps are sent upon some condition change and the agent connects to the server on port as opposed to port on the agent side that is used for queries. Using traps may detect some short problems that occur amidst the query interval and may be missed by the query data.