cirron

= Cirron

Cirron measures a piece of Ruby code and reports back several performance counters: CPU instruction count, branch misses, page faults and time spent measuring. It uses the Linux perf events interface or @ibireme's KPC demo[https://gist.github.com/ibireme/173517c208c7dc333ba962c1f0d67d12] on OSX.

It can also trace syscalls using +strace+, Linux only!

== Prerequisites

• Linux with perf events support / Apple ARM OSX
• C++
• Ruby 3.x

== Usage

=== Performance Counters $ sudo irb irb(main):001> require 'cirron' => true irb(main):002* c = Cirron::collector do irb(main):003* puts "Hello" irb(main):004> end Hello => Counter(time_enabled_ns: 110260, instruction_count: 15406, branch_misses: 525, page_faults: 0)

=== Tracing Syscalls

$ sudo irb irb> require 'cirron' => true irb> trace = Cirron::tracer do irb> # Your code here irb> puts "Hello" irb> end => [#<Syscall:0x00007c6c1a4b3608 @args="1, [{iov_base="Hello", iov_len=5}, {iov_base="\n", iov_len=1}], 2", @duration="0.000201", @name="writev", @pid="2261962", @retval="6", @timestamp="1720285300.334976">]

Save the trace for ingesting to Perfetto

irb> File.write("/tmp/trace", Cirron::to_tef(trace)) => 267

=== Tampering with Syscalls

Available tampering actions are: error: Inject a fault with the specified errno. retval: Inject a success with the specified return value. signal: Deliver the specified signal on syscall entry. delay_enter: Delay syscall entry by the specified time. delay_exit: Delay syscall exit by the specified time. poke_enter: Modify memory at argN on syscall entry. poke_exit: Modify memory at argN on syscall exit. syscall: Inject a different syscall instead.

The when argument can be used to specify when to perform the tampering.

See the Tampering section of the strace manual page for more detailed explanaition of the arguments.

$ sudo irb
irb> require 'cirron'

irb> injector = Cirron.injector
irb> injector.inject("openat", "error", "ENOSPC")
irb> injector.inject("openat", "delay_enter", "1s", when_condition="2+2")
irb> injector.run do
irb>     # Open now fails with "No space left on device" and every
irb>     # other call to `openat` will be delayed by 1s.
irb>     File.open("test.txt", "w")
irb> end

== Additional Information

For more detailed information, please visit the project's GitHub page: https://github.com/s7nfo/Cirron