merge: branch performance experiments

site/content/posts/2024-11-27-experiments-with-rust-nix-k6-parca/index.md → site/content/posts/2024-12-01-experiments-with-rust-nix-k6-parca/index.md

@@ -28,6 +28,10 @@ Over the past couple of weeks, I've been teaching myself [Rust](https://www.rust
 
 The Rust language also encourages the ideas of safety and soundness - sound code is (approximately) code that can't cause memory corruption or exhibit undefined behaviour. You can read more in this excellent post [Safety and Soundness in Rust](https://jacko.io/safety_and_soundness.html).
 
+This blog post started out life as a post about Rust and my experience learning it, but I got interested in the performance of the server implementation I came up with and the post evolved into a post more about profiling and load testing!
+
+## Learning Rust
+
 It's been a little while since I dug into a new programming language, so I thought I'd mention how I went about it. In general I'm someone who learns best "by doing". I normally try to read through some of the basic concepts, then jump to a project that will enable me to exercise them quite quickly. Fortunately, Rust has an _excellent_ official guide in the form of the [Rust Book](https://doc.rust-lang.org/book/), which covers everything from the obligatory `Hello, World!`, to concurrency, memory safety, publishing packages on [crates.io](https://crates.io) and more. I thoroughly recommend it.
 
 I've also picked up a copy of [Rust for Rustaceans](https://rust-for-rustaceans.com/) which was recommended by a couple of different colleagues - I intend to work through this next.
@@ -64,7 +68,10 @@ I've been looking for an excuse to play with [k6](https://k6.io/) for a while. A
 In very simple terms, to use `k6` you define a script (in Javascript) that outlines a set of requests to make, their success criteria and (optionally) the strategy for ramping up load on the server. It has _many_ more features than I used for this project, but I was impressed with how simple it was to get started. I began by running the following (grabbing `k6` from `nixpkgs`):
 
 ```shell
-❯ nix run github:NixOS/nixpkgs/nixos-unstable#k6 -- new
+# Start a shell with k6 available
+❯ nix shell github:NixOS/nixpkgs/nixos-unstable#k6
+# Init a new k6 script
+❯ k6 new
 Initialized a new k6 test script in script.js. You can now execute it by running `k6 run script.js`.
 ```
 
@@ -88,16 +95,19 @@ VUs are an emulation of a user interacting with your service; each of them is an
 I wanted to test a variety of requests, so I first generated a list of valid URLs for my server. I used [`cariddi`](https://github.com/edoardottt/cariddi) which is a web crawler written in Go, combined with `jq` to create a list of valid paths in a JSON file:
 
 ```shell
-echo http://localhost:8080 \
-  | nix run github:NixOS/nixpkgs/nixos-unstable#cariddi -- -plain \
+# Start a shell with k6 available
+❯ nix shell github:NixOS/nixpkgs/nixos-unstable#cariddi
+# Run cariddi and generate the paths.json
+❯ echo http://localhost:8080 \
+  | cariddi -- -plain \
   | cut -d"/" -f4- \
   | jq -r -nR '[inputs | select(length>0)]' > paths.json
 ```
 
 Similarly I generated a list of valid redirects:
 
 ```shell
-curl -s "https://gist.githubusercontent.com/jnsgruk/b590f114af1b041eeeab3e7f6e9851b7/raw" \
+❯ curl -s "https://gist.githubusercontent.com/jnsgruk/b590f114af1b041eeeab3e7f6e9851b7/raw" \
     | cut -d" " -f1 \
     | jq -r -nR '[inputs | select(length>0)]' > redirects.json
 ```
@@ -138,7 +148,7 @@ You can see my final test script [on Github](https://github.com/jnsgruk/server-b
 Finally, I ran `k6` and let it rip! This initial run was against `servy`, running on my workstation:
 
 ```shell
-❯ nix run github:NixOS/nixpkgs/nixos-unstable#k6 -- run script.js
+❯ k6 run script.js
 
          /\      Grafana   /‾‾/
     /\  /  \     |\  __   /  /
@@ -317,14 +327,16 @@ info "Results available in summary-${1}.txt, summary-${1}.json and summary-${1}.
 This was the final piece of the puzzle for now; after building [and packaging](https://github.com/jnsgruk/server-bench/blob/6db6c179649f44bb2f0fcc6a2441d8fc38b24f03/flake.nix#L60-L67) this script and [defining the test VM as a package](https://github.com/jnsgruk/server-bench/blob/6db6c179649f44bb2f0fcc6a2441d8fc38b24f03/flake.nix#L50) in the flake, I'd enabled the following workflow:
 
 ```shell
+# Start the devShell for the server-bench project
+❯ nix develop github:jnsgruk/server-bench
 # Build & run the VM
-❯ nix run .#benchvm -- --daemonize --display none
+❯ run-benchvm-vm --daemonize --display none
 # Start, and load test the gosherve based server
-❯ nix run .#benchvm-test -- jnsgruk-go
+❯ benchvm-test jnsgruk-go
 # Start, and load test the Rust based server
-❯ nix run .#benchvm-test -- jnsgruk-rust
+❯ benchvm-test jnsgruk-rust
 # All done, power down the VM
-❯ nix run .#benchvm-exec -- poweroff
+❯ benchvm-exec poweroff
 ```
 
 Excellent! Now on to some actual testing!
@@ -515,10 +527,13 @@ If you do play with the profile on `pprof.me`, try filtering by function name an
 
 [![filtering by function name on pprof.me](06.png)](06.png)
 
-By the time you read this, the [`parca-agent` should be upstream](https://github.com/NixOS/nixpkgs/pull/360132) into `nixpkgs`, so you can do something like this:
+By the time you read this, the [`parca-agent` should be upstream](https://github.com/NixOS/nixpkgs/pull/360132) into `nixpkgs`, but in the mean time you can pull the package I included in the `server-bench` repo and use that:
 
 ```shell
-❯ sudo nix run github:NixOS/nixpkgs/nixos-unstable#parca-agent -- \
+# Start the devShell for the server-bench project
+❯ nix develop github:jnsgruk/server-bench
+# Start the agent
+❯ sudo parca-agent -- \
   --remote-store-address="grpc.polarsignals.com:443" \
   --remote-store-bearer-token="$TOKEN" \
   --node="$HOSTNAME"
@@ -760,17 +775,16 @@ I also added a [new flake input](https://github.com/jnsgruk/server-bench/blob/6d
 As such, if you want to try reproducing any of these results and measure old vs. new vs. `servy`, you just need to do the following:
 
 ```shell
+# Start the devShell for the server-bench project
+❯ nix develop github:jnsgruk/server-bench
 # Build & run the VM
-❯ nix run github:jnsgruk/server-bench#benchvm -- --daemonize --display none
-
+❯ run-benchvm-vm --daemonize --display none
 # Edit the core/memory count as required
 ❯ vim vm.nix
-
 # Start, and load test a server, choosing your variety
-❯ nix run github:jnsgruk/server-bench#benchvm-test -- <jnsgruk-go-old|jnsgruk-go|jnsgruk-rust>
-
+❯ benchvm-test <jnsgruk-go-old|jnsgruk-go|jnsgruk-rust>
 # Power down the VM
-❯ nix run github:jnsgruk/server-bench#benchvm-exec -- poweroff
+❯ benchvm-exec poweroff
 ```
 
 The results will be gathered in a collection of `summary-*.<txt|html|json>` files for you to inspect.