| 1 | #!/usr/bin/env bash |
| 2 | # |
| 3 | # Dogfood — load test against a large repository (spec §11, M6). |
| 4 | # |
| 5 | # > load test against a large repository (use the Linux kernel or the jj repo |
| 6 | # > itself) |
| 7 | # |
| 8 | # ./scripts/loadtest.sh [URL] [CONCURRENCY] [DURATION_SECONDS] |
| 9 | # |
| 10 | # What this measures, and why these three things: |
| 11 | # |
| 12 | # * **Cold browse.** Tree and blob pages on a large repository, with the |
| 13 | # highlight cache empty. This is the worst case the cache exists to remove, |
| 14 | # and the number to compare against the warm run. |
| 15 | # * **Warm browse.** The same pages again. If warm is not dramatically faster |
| 16 | # than cold, the highlight cache is not working, which is the §8 performance |
| 17 | # mistake spelled out by name. |
| 18 | # * **The change list.** Spec §4 calls it "the hottest page in the product", |
| 19 | # and it is the one that reads precomputed stack edges rather than walking |
| 20 | # the commit graph — so a regression there is a regression in that decision. |
| 21 | # |
| 22 | # It drives the *public* HTTP surface with curl, so it measures what a user |
| 23 | # experiences rather than what a benchmark harness inside the process would. |
| 24 | |
| 25 | set -euo pipefail |
| 26 | |
| 27 | URL="" |
| 28 | CONCURRENCY="" |
| 29 | DURATION="" |
| 30 | |
| 31 | c_green() { printf '\033[32m%s\033[0m\n' "$*"; } |
| 32 | c_dim() { printf '\033[2m%s\033[0m\n' "$*"; } |
| 33 | c_red() { printf '\033[31m%s\033[0m\n' "$*" >&2; } |
| 34 | |
| 35 | command -v curl >/dev/null || { c_red "curl is required"; exit 1; } |
| 36 | |
| 37 | # ─── pick a target ─────────────────────────────────────────────────────────── |
| 38 | |
| 39 | # The repository to hammer. Overridable, because "a large repository" is |
| 40 | # whatever the instance actually has — the point is that it is large, not that |
| 41 | # it is a particular one. |
| 42 | REPO_PATH="" |
| 43 | |
| 44 | # A file inside that repository with a grammar behind it, so the cold/warm |
| 45 | # comparison actually measures highlighting. A path that does not exist would |
| 46 | # 404 in microseconds and make the cache look infinitely fast. |
| 47 | BLOB_PATH="" |
| 48 | |
| 49 | if [[ -z "$REPO_PATH" ]]; then |
| 50 | c_red "Set DF_LOADTEST_REPO to a repository path, e.g. DF_LOADTEST_REPO=/dogfood/linux" |
| 51 | echo |
| 52 | echo "Import one first:" |
| 53 | echo " jj git clone --colocate https://github.com/jj-vcs/jj /tmp/jj" |
| 54 | echo " cd /tmp/jj && jj git remote add dogfood $URL/<owner>/jj.git && jj git push --all" |
| 55 | exit 1 |
| 56 | fi |
| 57 | |
| 58 | # ─── helpers ───────────────────────────────────────────────────────────────── |
| 59 | |
| 60 | # One sample per line: seconds, then status. |
| 61 | # |
| 62 | # The newline is part of the same write. Several workers append to one file |
| 63 | # concurrently, and a write short enough to be atomic keeps their lines from |
| 64 | # interleaving — which is why this is not `curl … && echo`. |
| 65 | timed() { |
| 66 | curl -s -o /dev/null -w '%{time_total} %{http_code}\n' --max-time 60 "$1" |
| 67 | } |
| 68 | |
| 69 | # Drive one path with N workers for D seconds; print count, error count, and the |
| 70 | # p50/p95/p99 of the response times. |
| 71 | # |
| 72 | # Percentiles rather than a mean: spec §10 says to alert on push latency p99, and |
| 73 | # a mean hides exactly the tail that matters on a large repository. |
| 74 | hammer() { |
| 75 | local label="$1" path="$2" |
| 76 | local tmp |
| 77 | tmp="" |
| 78 | |
| 79 | local deadline=$((SECONDS + DURATION)) |
| 80 | for _ in ; do |
| 81 | ( |
| 82 | while [[ $SECONDS -lt $deadline ]]; do |
| 83 | timed "$URL$path" >> "$tmp" || true |
| 84 | done |
| 85 | ) & |
| 86 | done |
| 87 | wait |
| 88 | |
| 89 | # Percentiles are computed over *successful* requests only. A 429 returns in |
| 90 | # microseconds, so mixing them in would report a rate-limited run as the |
| 91 | # fastest one — the opposite of the truth. |
| 92 | local total ok throttled failed |
| 93 | total="" |
| 94 | ok="" |
| 95 | throttled="" |
| 96 | failed=$((total - ok - throttled)) |
| 97 | |
| 98 | # `asort` is a gawk extension the default Debian `mawk` does not have, so |
| 99 | # sorting happens in sort(1) and awk only indexes. |
| 100 | awk '$2 == 200 { print $1 * 1000 }' "$tmp" | sort -n | awk \ |
| 101 | -v label="$label" -v ok="$ok" -v throttled="$throttled" -v failed="$failed" ' |
| 102 | { t[NR] = $1 } |
| 103 | END { |
| 104 | n = NR |
| 105 | if (n == 0) { |
| 106 | printf "%-22s ok=0 throttled=%-5d failed=%-4d (no successful samples)\n", |
| 107 | label, throttled, failed |
| 108 | exit |
| 109 | } |
| 110 | i50 = int(n * 0.50); if (i50 < 1) i50 = 1 |
| 111 | i95 = int(n * 0.95); if (i95 < 1) i95 = 1 |
| 112 | i99 = int(n * 0.99); if (i99 < 1) i99 = 1 |
| 113 | printf "%-22s ok=%-6d throttled=%-5d failed=%-4d p50=%7.1fms p95=%7.1fms p99=%7.1fms\n", |
| 114 | label, ok, throttled, failed, t[i50], t[i95], t[i99] |
| 115 | } |
| 116 | ' |
| 117 | |
| 118 | rm -f "$tmp" |
| 119 | } |
| 120 | |
| 121 | # ─── run ───────────────────────────────────────────────────────────────────── |
| 122 | |
| 123 | echo "Dogfood load test" |
| 124 | echo " target $URL$REPO_PATH" |
| 125 | echo " concurrency $CONCURRENCY" |
| 126 | echo " duration s per phase" |
| 127 | echo |
| 128 | |
| 129 | # Reachability first, so a typo in the URL fails in one second rather than after |
| 130 | # four phases of zeros. |
| 131 | code="" |
| 132 | [[ "$code" == "200" ]] || { c_red "$URL$REPO_PATH returned $code — is it public?"; exit 1; } |
| 133 | |
| 134 | c_dim "phase 1: cold browse (highlight cache may be empty)" |
| 135 | hammer "tree (cold)" "$REPO_PATH" |
| 136 | hammer "blob (cold)" "$REPO_PATH$BLOB_PATH" |
| 137 | |
| 138 | c_dim "phase 2: warm browse (same pages, cache populated)" |
| 139 | hammer "tree (warm)" "$REPO_PATH" |
| 140 | hammer "blob (warm)" "$REPO_PATH$BLOB_PATH" |
| 141 | |
| 142 | c_dim "phase 3: the hottest page (spec §4)" |
| 143 | hammer "change list" "$REPO_PATH/changes" |
| 144 | hammer "change list (all)" "$REPO_PATH/changes?state=all" |
| 145 | |
| 146 | c_dim "phase 4: history and bookmarks" |
| 147 | hammer "log" "$REPO_PATH/log?limit=100" |
| 148 | hammer "bookmarks" "$REPO_PATH/bookmarks" |
| 149 | |
| 150 | echo |
| 151 | c_green "done" |
| 152 | echo |
| 153 | echo "What to look for:" |
| 154 | echo " · blob (warm) should be several times faster than blob (cold). If it is" |
| 155 | echo " not, the highlight cache is not being hit — spec §8 calls that 'the" |
| 156 | echo " easiest performance mistake to make here'." |
| 157 | echo " · throttled > 0 is the rate limiter working as designed (spec §9): every" |
| 158 | echo " request here comes from one address, so at concurrency it will" |
| 159 | echo " engage. Percentiles above are over successful requests only." |
| 160 | echo " · failed > 0 is a real problem — a timeout or a 5xx." |
| 161 | echo " · the change list should not degrade with repository size — it reads" |
| 162 | echo " precomputed stack edges, never the commit graph (spec §4)." |
162 lines · Shell