From b32e961a844121ed71f7f1e82011fea2d8e3469f Mon Sep 17 00:00:00 2001 From: Andreas Kling Date: Wed, 11 Dec 2019 20:36:56 +0100 Subject: Kernel: Implement a simple process time profiler The kernel now supports basic profiling of all the threads in a process by calling profiling_enable(pid_t). You finish the profiling by calling profiling_disable(pid_t). This all works by recording thread stacks when the timer interrupt fires and the current thread is in a process being profiled. Note that symbolication is deferred until profiling_disable() to avoid adding more noise than necessary to the profile. A simple "/bin/profile" command is included here that can be used to start/stop profiling like so: $ profile 10 on ... wait ... $ profile 10 off After a profile has been recorded, it can be fetched in /proc/profile There are various limits (or "bugs") on this mechanism at the moment: - Only one process can be profiled at a time. - We allocate 8MB for the samples, if you use more space, things will not work, and probably break a bit. - Things will probably fall apart if the profiled process dies during profiling, or while extracing /proc/profile --- Libraries/LibC/serenity.cpp | 11 +++++++++++ Libraries/LibC/serenity.h | 3 +++ 2 files changed, 14 insertions(+) (limited to 'Libraries') diff --git a/Libraries/LibC/serenity.cpp b/Libraries/LibC/serenity.cpp index 22756fe6a9..4d26facc60 100644 --- a/Libraries/LibC/serenity.cpp +++ b/Libraries/LibC/serenity.cpp @@ -16,4 +16,15 @@ int module_unload(const char* name, size_t name_length) __RETURN_WITH_ERRNO(rc, rc, -1); } +int profiling_enable(pid_t pid) +{ + int rc = syscall(SC_profiling_enable, pid); + __RETURN_WITH_ERRNO(rc, rc, -1); +} + +int profiling_disable(pid_t pid) +{ + int rc = syscall(SC_profiling_disable, pid); + __RETURN_WITH_ERRNO(rc, rc, -1); +} } diff --git a/Libraries/LibC/serenity.h b/Libraries/LibC/serenity.h index 26e0ebc5b6..6aa6026185 100644 --- a/Libraries/LibC/serenity.h +++ b/Libraries/LibC/serenity.h @@ -41,4 +41,7 @@ __BEGIN_DECLS int module_load(const char* path, size_t path_length); int module_unload(const char* name, size_t name_length); +int profiling_enable(pid_t); +int profiling_disable(pid_t); + __END_DECLS -- cgit v1.2.3