lix/src/libexpr/function-trace.hh

#pragma once

#include "eval.hh"

#include <chrono>

namespace nix {

struct FunctionCallTrace
{
    const Pos pos;
    FunctionCallTrace(const Pos & pos);
    ~FunctionCallTrace();
};
}
Track function start and ends for flame graphs With this patch, and this file I called `log.py`: #!/usr/bin/env nix-shell #!nix-shell -i python3 -p python3 --pure import sys from pprint import pprint stack = [] timestack = [] for line in open(sys.argv[1]): components = line.strip().split(" ", 2) if components[0] != "function-trace": continue direction = components[1] components = components[2].rsplit(" ", 2) loc = components[0] _at = components[1] time = int(components[2]) if direction == "entered": stack.append(loc) timestack.append(time) elif direction == "exited": dur = time - timestack.pop() vst = ";".join(stack) print(f"{vst} {dur}") stack.pop() and: nix-instantiate --trace-function-calls -vvvv ../nixpkgs/pkgs/top-level/release.nix -A unstable > log.matthewbauer 2>&1 ./log.py ./log.matthewbauer > log.matthewbauer.folded flamegraph.pl --title matthewbauer-post-pr log.matthewbauer.folded > log.matthewbauer.folded.svg I can make flame graphs like: http://gsc.io/log.matthewbauer.folded.svg --- Includes test cases around function call failures and tryEval. Uses RAII so the finish is always called at the end of the function. 2019-04-12 16:31:33 +00:00			`#pragma once`

			`#include "eval.hh"`
Move #include (cherry picked from commit 8beedd44861d1fe7208609ee8d231ca1c02dedf6) 2019-11-13 16:38:37 +00:00
			`#include <chrono>`
Track function start and ends for flame graphs With this patch, and this file I called `log.py`: #!/usr/bin/env nix-shell #!nix-shell -i python3 -p python3 --pure import sys from pprint import pprint stack = [] timestack = [] for line in open(sys.argv[1]): components = line.strip().split(" ", 2) if components[0] != "function-trace": continue direction = components[1] components = components[2].rsplit(" ", 2) loc = components[0] _at = components[1] time = int(components[2]) if direction == "entered": stack.append(loc) timestack.append(time) elif direction == "exited": dur = time - timestack.pop() vst = ";".join(stack) print(f"{vst} {dur}") stack.pop() and: nix-instantiate --trace-function-calls -vvvv ../nixpkgs/pkgs/top-level/release.nix -A unstable > log.matthewbauer 2>&1 ./log.py ./log.matthewbauer > log.matthewbauer.folded flamegraph.pl --title matthewbauer-post-pr log.matthewbauer.folded > log.matthewbauer.folded.svg I can make flame graphs like: http://gsc.io/log.matthewbauer.folded.svg --- Includes test cases around function call failures and tryEval. Uses RAII so the finish is always called at the end of the function. 2019-04-12 16:31:33 +00:00
			`namespace nix {`

			`struct FunctionCallTrace`
			`{`
replace most Pos objects/ptrs with indexes into a position table Pos objects are somewhat wasteful as they duplicate the origin file name and input type for each object. on files that produce more than one Pos when parsed this a sizeable waste of memory (one pointer per Pos). the same goes for ptr<Pos> on 64 bit machines: parsing enough source to require 8 bytes to locate a position would need at least 8GB of input and 64GB of expression memory. it's not likely that we'll hit that any time soon, so we can use a uint32_t index to locate positions instead. 2022-03-04 18:31:59 +00:00			`const Pos pos;`
Hide FunctionCallTrace constructor/destructor This prevents them from being inlined. On gcc 9, this reduces the stack size needed for nix-instantiate '<nixpkgs>' -A texlive.combined.scheme-full --dry-run from 12.9 MiB to 4.8 MiB. 2020-01-05 15:21:34 +00:00			`FunctionCallTrace(const Pos & pos);`
			`~FunctionCallTrace();`
Track function start and ends for flame graphs With this patch, and this file I called `log.py`: #!/usr/bin/env nix-shell #!nix-shell -i python3 -p python3 --pure import sys from pprint import pprint stack = [] timestack = [] for line in open(sys.argv[1]): components = line.strip().split(" ", 2) if components[0] != "function-trace": continue direction = components[1] components = components[2].rsplit(" ", 2) loc = components[0] _at = components[1] time = int(components[2]) if direction == "entered": stack.append(loc) timestack.append(time) elif direction == "exited": dur = time - timestack.pop() vst = ";".join(stack) print(f"{vst} {dur}") stack.pop() and: nix-instantiate --trace-function-calls -vvvv ../nixpkgs/pkgs/top-level/release.nix -A unstable > log.matthewbauer 2>&1 ./log.py ./log.matthewbauer > log.matthewbauer.folded flamegraph.pl --title matthewbauer-post-pr log.matthewbauer.folded > log.matthewbauer.folded.svg I can make flame graphs like: http://gsc.io/log.matthewbauer.folded.svg --- Includes test cases around function call failures and tryEval. Uses RAII so the finish is always called at the end of the function. 2019-04-12 16:31:33 +00:00			`};`
			`}`