is not substantial, but benchmarks that measure very short execution times are likely to be skewed due to this overhead. A number of tools have been introduced to improve this situation. The first such tool was Apache's mod_perl, which sought to address one of the most-common reasons that small Perl programs were invoked rapidly: CGI Web development. ActivePerl, via Microsoft ISAPI, provides similar performance improvements. Once Perl code is compiled, there is additional overhead during the execution phase that typically isn't present for programs written in compiled languages such as C or C++. Examples of such overhead include bytecode interpretation, reference-counting memory management, and dynamic type-checking. Optimizing The most critical routines can be written in other languages (such as C), which can be connected to Perl via simple Inline modules or the more complex, but flexible, XS mechanism. Perl 5 Perl 5, the language usually referred to as "Perl", continues to be actively developed. Perl 5.12.0 was released in April 2010 with some new features influenced by the design of Perl 6, followed by Perl 5.14.1 (released on June 17, 2011), Perl 5.16.1 (released on August 9, 2012.), and Perl 5.18.0 (released on May 18, 2013). Perl 5 development versions are released on a monthly basis, with major releases coming out once per year. The relative proportion of Internet searches for "Perl programming", as compared with similar searches for other programming languages, steadily declined from about 10% in 2005 to about 2% in 2011, and to about 0.7% in 2020. Raku (Perl 6) At the 2000 Perl Conference, Jon Orwant made a case for a major new language-initiative. This led to a decision to begin work on a redesign of the language, to be called Perl 6. Proposals for new language features were solicited from the Perl community at large, which submitted more than 300 RFCs. Wall spent the next few years digesting the RFCs and synthesizing them into a coherent framework for Perl 6. He presented his design for Perl 6 in a series of documents called "apocalypses"numbered to correspond to chapters in Programming Perl. , the developing specification of Perl 6 was encapsulated in design documents called Synopsesnumbered to correspond to Apocalypses. Thesis work by Bradley M. Kuhn, overseen by Wall, considered the possible use of the Java virtual machine as a runtime for Perl. Kuhn's thesis showed this approach to be problematic. In 2001, it was decided