feat(fs): fs_startupTiming for FS_Startup wall time; PR hygiene docs

CONTRIBUTING.md

@@ -42,6 +42,10 @@ If you are interested to participate, ensure to read first our contribution guid
 * [How to commit your code](https://github.com/etlegacy/etlegacy/wiki/How-to-commit-Your-Code)
 * [Coding conventions](https://github.com/etlegacy/etlegacy/wiki/Coding-Conventions)
 
+## PULL REQUESTS
+
+Rebase onto **current `main`** before review, and avoid PRs that would **revert** unrelated landed changes. Close obsolete PRs that are superseded or remain **unmergeable** after a rebase.
+
 ## UPSTREAM AND FORKS
 
 To pull the latest changes from the main ET: Legacy repository without merging yet:

README.md

@@ -106,6 +106,10 @@ GitHub Actions on **`main`** / **`master`** run **[`.github/workflows/ci.yml`](.
 
 Forks without **`LEGACY_CI_WEBHOOK`** still get a full CI signal; the optional Discord notify step is skipped when that secret is unset. The **`check-compiler-warnings`** job scans native build logs for new compiler warnings in game code; **Android** and **Windows** (`win` / `win64`) logs are treated as informational only (see `misc/collect-and-check-gh-build-logs.py`).
 
+**Pull request hygiene:** Before merging, confirm the branch is **rebased on current `main`** and does not revert unrelated work. Close or update stale PRs that show **merge conflicts** against `main`.
+
+**Measuring filesystem startup:** Use **`+set fs_startupTiming 1`** on the command line (or set `fs_startupTiming` to `1` in the console before a full FS re-init). The log prints **`FS startup wall time: N ms`** after pk3 search paths are built. For per-frame timing once running, use **`com_speeds`**.
+
 ## Development helpers
 
 [Pixi](https://pixi.sh/) workspace: **`pixi.toml`**.

src/qcommon/files.c

@@ -256,6 +256,7 @@ typedef struct searchpath_s
  */
 char                fs_gamedir[MAX_OSPATH];
 static cvar_t       *fs_debug;
+static cvar_t       *fs_startupTiming;
 static cvar_t       *fs_homepath;
 static cvar_t       *fs_basepath;
 static cvar_t       *fs_basegame;
@@ -4502,14 +4503,17 @@ static void FS_Startup(const char *gameName)
 {
 	const char *homePath;
 	int        i;
+	int        fs_startup_begin_ms;
 
 	Com_Printf("----- Initializing Filesystem --\n");
 
 	fs_packFiles = 0;
 
-	fs_debug    = Cvar_Get("fs_debug", "0", 0);
-	fs_basepath = Cvar_Get("fs_basepath", Sys_DefaultInstallPath(), CVAR_INIT | CVAR_PROTECTED);
-	fs_basegame = Cvar_Get("fs_basegame", "", CVAR_INIT | CVAR_PROTECTED);
+	fs_debug            = Cvar_Get("fs_debug", "0", 0);
+	fs_startupTiming    = Cvar_Get("fs_startupTiming", "0", CVAR_TEMP);
+	fs_startup_begin_ms = Sys_Milliseconds();
+	fs_basepath         = Cvar_Get("fs_basepath", Sys_DefaultInstallPath(), CVAR_INIT | CVAR_PROTECTED);
+	fs_basegame         = Cvar_Get("fs_basegame", "", CVAR_INIT | CVAR_PROTECTED);
 
 	homePath = Sys_DefaultHomePath();
 
@@ -4615,6 +4619,11 @@ static void FS_Startup(const char *gameName)
 
 #endif // ifndef DEDICATED
 
+	if (fs_startupTiming->integer)
+	{
+		Com_Printf("FS startup wall time: %i ms\n", Sys_Milliseconds() - fs_startup_begin_ms);
+	}
+
 	Com_Printf("--------------------------------\n");
 }