From 1100562e29f6476448b656dbddd4cf22505523f6 Mon Sep 17 00:00:00 2001
From: Mitja Felicijan <mitja.felicijan@gmail.com>
Date: Sun, 10 Mar 2024 14:59:14 +0100
Subject: Move back to JBMAFP

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+---
+title: Converting Valgrind callgrinds to SVG format
+url: /converting-valgrind-callgrinds-to-svg-format.html
+date: 2024-02-28T03:23:00+01:00
+type: post
+draft: false
+---
+
+Lately I have been doing a lot of systems programming and profiling is
+the name of the game when it comes to developing good software.
+
+I found [Valgrind](https://valgrind.org) indispensable for profiling
+and getting callgraphs.
+
+Most of the time there are better alternatives that SVG to drill intro the
+callgraphs but if you need to put put a callgraph on a webpage or maybe
+send it to somebody that does not have all of the necessary software to
+view these things then SVG is the perfect format for this.
+
+Theses are couple of amazing applications to view callgraphs that get
+exported by [Valgrind](https://valgrind.org):
+
+- [Kcachegrind](https://kcachegrind.github.io/html/Home.html) - Linux
+- [WinCacheGrind](https://ceefour.github.io/wincachegrind/) - Windows
+- [Profiling Viewer](https://profilingviewer.com/) - macOS
+
+This is how Kcachekrind looks with a callgraph loaded in. Not only that,
+with Kcachegrind you can also explore assembly produced by the compiler
+and get much more insight into the profile of your application.
+
+![Kcachekrind screenshot](/assets/posts/valgrind-callgrind-svg/kcachegrind.png)
+
+After this point you will need couple of things installed on your
+system. I will show how you do this on Fedora 39.
+
+```sh
+# Install valgrind which will do the actual profiling.
+sudo dnf install valgrind
+
+# Install Kcachegrind for local visualizing.
+sudo dnf install kcachegrind
+
+# Install gprof2dot for conversion from .dot to .svg.
+pip install gprof2dot  
+```
+
+Let's make a simple C program and test out profiling and the whole shebang.
+
+```c
+#include <stdio.h>
+
+int main() {
+  printf("Oh, hi Mark\n");
+  return 0;
+}
+```
+
+Then let's compile, convert to dot and then SVG file.
+
+```shell
+clang hi.c -o c-hi
+valgrind --tool=callgrind --dump-instr=yes --collect-jumps=yes ./c-hi
+gprof2dot --format=callgrind --output=out.c.dot --colormap=print callgrind.out.546168
+cat out.c.dot | dot -Tsvg > out.c.svg
+```
+
+This gives us an SVG file like this.
+
+![SVG callgrind for C program](/assets/posts/valgrind-callgrind-svg/out.c.svg)
+
+And this also works on other binaries.
+
+Lets give Zig a go.
+
+```zig
+const std = @import("std");
+
+pub fn main() !void {
+  std.debug.print("Oh, hi Mark!\n", .{});
+}
+```
+
+Now repeat the whole compile, convert cycle.
+
+```shell
+zig build-exe hi.zig --name zig-hi
+valgrind --tool=callgrind --dump-instr=yes --collect-jumps=yes ./zig-hi
+gprof2dot --format=callgrind --output=out.zig.dot --colormap=print callgrind.out.546168
+cat out.zig.dot | dot -Tsvg > out.zig.svg
+```
+
+![SVG callgrind for Zig program](/assets/posts/valgrind-callgrind-svg/out.zig.svg)
+
+Now, to be fair
+[Kcachegrind](https://kcachegrind.github.io/html/Home.html) is much nicer
+for local exploration and digging deep into the callgraphs, but the SVG
+format can still provide valid information for documentation and things
+of that nature.
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