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Cleanup IO wait and GC stacks from stackprof https://github.com/tmm1/stackprof/issues/36#issuecomment-1500525503
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| # frozen_string_literal: true | |
| require "stackprof" | |
| require "optparse" | |
| require "yaml" | |
| require "json" | |
| # To use run the script with: ruby cleanup_io_wait_and_gc_stacks.rb -s source_file.json -d destination_file.json | |
| # To avoid interrupting the root frames when IO wait or garbage collection happens we modify the raw data to merge | |
| # these stacks into the previous stacks or append previous stacks in the current stack. | |
| # | |
| # We are currently only updating the raw data and not the frames data. This is enough to make this display the data | |
| # correctly in speedscope but it might not be enough for other tools, including the stackprof reports. | |
| # | |
| # We are also only supporting Puma IO wait, we will need to update this script to support other servers. | |
| GC_FRAME_ID = 1 # This is static as defined in ext/stackprof/stackprof.c | |
| IO_FRAME_NAMES = ["Puma::Single#run", "Puma::Cluster::Worker#run"].freeze | |
| def cleanup_io_wait_and_gc_stacks(result) | |
| raw = result[:raw] | |
| frames = result[:frames] | |
| updated_raw = [] | |
| previous_stack = nil | |
| current_stack = nil | |
| # Currently we are only supporting transforming puma IO wait | |
| io_wait_frame_id = frames.find { |_key, frame| IO_FRAME_NAMES.include?(frame[:name]) }&.fetch(0)&.to_i | |
| io_wait_root_frame_id = nil | |
| index = 0 | |
| while (current_stack_height = raw[index]) | |
| index += 1 | |
| # We first get current_stack including the current stack number of samples and pop it out leaving only the stack | |
| # in current_stack | |
| current_stack = raw.slice(index, current_stack_height + 1) | |
| current_stack_samples_count = current_stack.pop | |
| # Leave index at the start of the next stack | |
| index += current_stack_height + 1 | |
| # First iteration we just push the current stack | |
| if previous_stack.nil? | |
| updated_raw.push(current_stack_height, *current_stack, current_stack_samples_count) | |
| previous_stack = current_stack | |
| next | |
| end | |
| # When we know puma io wait frame exists we can check if current stack last frame is the io wait frame | |
| if io_wait_frame_id && current_stack[-1] == io_wait_frame_id | |
| # Update previous stack sample count if previous stack is io wait | |
| if previous_stack[-1] == io_wait_root_frame_id | |
| updated_raw[-1] += current_stack_samples_count | |
| next | |
| end | |
| # First time we encounter io wait we need to update the frame name so it is displayed correctly in the UI | |
| if io_wait_root_frame_id.nil? | |
| io_wait_root_frame_id = current_stack[0] | |
| frames[current_stack[0]] = frames[current_stack[0]].merge(name: "(io wait)", file: nil) | |
| end | |
| # When previous stack is gc we need to remove the gc frames from the previous stack before appending | |
| if (previous_stack_gc_frame_index = previous_stack.find_index(GC_FRAME_ID)) | |
| new_stack = previous_stack[0..previous_stack_gc_frame_index - 1] + [current_stack[0]] | |
| updated_raw.push(new_stack.length, *new_stack, current_stack_samples_count) | |
| previous_stack = new_stack | |
| next | |
| end | |
| # Otherwise we just append the current stack to the previous stack | |
| new_stack = previous_stack + [current_stack[0]] | |
| updated_raw.push(previous_stack.length + 1, *new_stack, current_stack_samples_count) | |
| previous_stack = new_stack | |
| next | |
| end | |
| # If current stack is not GC we don't need to do anything and just return the current stack | |
| if current_stack[0] != GC_FRAME_ID | |
| updated_raw.push(current_stack_height, *current_stack, current_stack_samples_count) | |
| previous_stack = current_stack | |
| next | |
| end | |
| previous_stack_gc_frame_index = previous_stack.find_index(GC_FRAME_ID) | |
| # If the previous stack doesn't have GC we can append the current stack to the previous stack | |
| if previous_stack_gc_frame_index.nil? | |
| # When previous stack is io wait we need to remove the io wait frame from the previous stack before appending | |
| if previous_stack[-1] == io_wait_root_frame_id | |
| new_stack = previous_stack[0..-2] + current_stack | |
| updated_raw.push(new_stack.length, *new_stack, current_stack_samples_count) | |
| previous_stack = new_stack | |
| next | |
| end | |
| # Otherwise we just append the current stack to the previous stack | |
| new_stack = previous_stack + current_stack | |
| updated_raw.push(previous_stack.length + current_stack_height, *new_stack, current_stack_samples_count) | |
| previous_stack = new_stack | |
| next | |
| end | |
| # If the previous gc frames are the same as the current gc frames (Array of frame IDs are the same) we update the | |
| # previous stack by adding the current stack number of samples | |
| if previous_stack[previous_stack_gc_frame_index..] == current_stack | |
| updated_raw[-1] += current_stack_samples_count | |
| else | |
| # Otherwise we find the previous stack frame before the GC frame and append the current stack to it | |
| new_stack = previous_stack[0..previous_stack_gc_frame_index - 1] + current_stack | |
| updated_raw.push(new_stack.length, *new_stack, current_stack_samples_count) | |
| end | |
| end | |
| result[:raw] = updated_raw | |
| result | |
| end | |
| options = {} | |
| parser = OptionParser.new do |opts| | |
| opts.banner = "Usage: cleanup_io_wait_and_gc_stacks.rb [options]" | |
| opts.on("-s", "--source file", "Source file") { |v| options[:source_file] = v } | |
| opts.on("-d", "--destination file", "Destination file") { |v| options[:destination_file] = v } | |
| end | |
| parser.parse! | |
| parser.abort(parser.help) if options.size != 2 | |
| results = cleanup_io_wait_and_gc_stacks(StackProf::Report.from_file(options[:source_file]).data) | |
| File.write(options[:destination_file], JSON.dump(results)) |
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