Ядро мен қосымшалар үшін динамикалық із кестесі DTrace

Dynamic tracing framework for kernel and applications

DTrace is a comprehensive dynamic tracing framework originally created by Sun Microsystems for troubleshooting kernel and application problems on production systems in real time. Originally developed for Solaris, it has since been released under the free Common Development and Distribution License (CDDL) in OpenSolaris and its descendant illumos, and has been ported to several other Unix like systems. DTrace can be used to get a global overview of a running system, such as the amount of memory, CPU time, filesystem and network resources used by the active processes. It can also provide much more fine grained information, such as a log of the arguments with which a specific function is being called, or a list of the processes accessing a specific file. In 2010, Oracle Corporation acquired Sun Microsystems and announced discontinuing OpenSolaris. As a community effort of some core Solaris engineers to create a truly open source Solaris, illumos operating system was announced via webinar on Thursday, 3 August 2010, as a fork on OpenSolaris OS/Net consolidation, including DTrace technology. In October 2011, Oracle announced the porting of DTrace to Linux, and in 2019 official DTrace for Fedora is available on GitHub. For several years an unofficial DTrace port to Linux was available, with no changes in licensing terms. In August 2017, Oracle released DTrace kernel code under the GPLv2+ license, and user space code under GPLv2 and UPL licensing. In September 2018 Microsoft announced that they had ported DTrace from FreeBSD to Windows. created by Brendan Gregg (author of the DTrace book), which also provides documentation and demonstrations of each.

DTrace first became available for use in November 2003, and was formally released as part of Sun's Solaris 10 in January 2005. DTrace was the first component of the OpenSolaris project to have its source code released under the Common Development and Distribution License (CDDL). DTrace is an integral part of illumos and related distributions. DTrace is a standard part of FreeBSD and NetBSD. Apple added DTrace support in Mac OS X 10.5 "Leopard", including a GUI called Instruments. Over 40 DTrace scripts from the DTraceToolkit are included in /usr/bin, including tools to examine disk I/O (iosnoop) and process execution (execsnoop). Unlike other platforms that DTrace is supported on, Mac OS X has a flag (P LNOATTACH) that a program may set that disallows tracing of that process by debugging utilities such as DTrace and gdb. In the original Mac OS X DTrace implementation, this could affect tracing of other system information, as unrelated probes that should fire while a program with this flag set was running would fail to do so. The OS X 10.5.3 update addressed this issue a few months later. However, since El Capitan, System Integrity Protection prevents user from DTracing protected binary by default. The Linux port of DTrace has been available since 2008; work continues actively to enhance and fix issues. There is also an active implementation on github. Standard core providers are available (fbt, syscall, profile), plus a special "instr" provider (some of the Solaris providers are not yet available ). The Linux DTrace implementation is a loadable kernel module, which means that the kernel itself requires no modification, and thus allows DTrace to avoid CDDL vs. GPL licensing conflicts (in its source form, at least). However, once DTrace is loaded the kernel instance will be marked as tainted. In 2007, a developer at QNX Software Systems announced on his blog that he and a colleague were working on incorporating DTrace into the QNX operating system. Oracle Corporation added beta DTrace support for Oracle Linux in 2011, General availability was announced in December 2012. On March 11, 2019, Microsoft released their build of DTrace for the Windows 10 insider builds.

With a supported language provider, DTrace can retrieve context of the code, including function, source file, and line number location. Further, dynamic memory allocation and garbage collection can be made available if supported by the language. Supported language providers include assembly language, C, C++, Java, Erlang, JavaScript, Perl, PHP, Python, Ruby, shell script, and Tcl. Application providers allow DTrace to follow the operation of applications through system calls and into the kernel. Applications that offer DTrace application providers include MySQL, PostgreSQL, Oracle Database, Oracle Grid Engine, and Firefox.

DTrace was designed and implemented by Bryan Cantrill, Mike Shapiro, and Adam Leventhal. The authors received recognition in 2005 for the innovations in DTrace from InfoWorld and Technology Review. DTrace won the top prize in The Wall Street Journals 2006 Technology Innovation Awards competition. The authors were recognized by USENIX with the Software Tools User Group (STUG) award in 2008.