Contents
What is perf data?
Perf is a profiler tool for Linux 2.6+ based systems that abstracts away CPU hardware differences in Linux performance measurements and presents a simple commandline interface. Perf is based on the perf_events interface exported by recent versions of the Linux kernel.
How do you annotate perf?
Live annotate with perf top You can also annotate using the perf top command. Run the perf top command and press ‘a’ on any particular symbol that you want to annotate. It also dynamically updates data at a fixed interval.
How does perf work Linux?
Using perf report you get the number of samples falling into your functions independently of their calling relations. Perf works on the Model Specific Registers of your CPU for measurements like cycles or branch-misses or so. A special Part called PMU(Performance Measurement Unit) is counting all kinds of events.
What does perf mean in texting?
PERF means “Perfect.” Like many slang words, the term PERF is formed by using just the few letters of the whole version. (Another popular term formed this way is GORG (gorgeous).)
What does OK perf mean?
What does Perfing mean?
transitive verb. 1 : to make a hole through especially : to make a line of holes in to facilitate separation. 2 : to pass through or into by or as if by making a hole.
How does perf report work in Stack Overflow?
The perf command you are using only sample your programs without recording any information of the call stack. Using perf report you get the number of samples falling into your functions independently of their calling relations. You can use the –call-graph option to get a tree when using perf report:
What are the options in the Perf record command?
The perf record command supports many options including the ability to start collection on an existing thread or process. The –call-graph option records caller/callee information (stack chain/backtrace).
How to make bogus call graphs in PERF?
In some systems, where binaries are build with gcc –fomit-frame-pointer, using the “fp” method will produce bogus call graphs, using “dwarf”, if available (perf tools linked to the libunwind or libdw library) should be used instead. Using the “lbr” method doesn’t require any compiler options.
What are the subsystems of the Perf system?
PERF consists of two major subsystems: A kernel SYSCALL that provides access to performance data including operating system software events and hardware performance events, and A collection of user-space tools to collect, display and analyze performance data.