runit-startuptime: new script

parse the timing info from dmesg to give uses a rough accounting of time
spent during boot. this may fail to be accurate if run a long time from boot
(i.e. if the messages have left the kernel message ring buffer)

Makefile

@@ -16,6 +16,7 @@ install:
 	install -m755 modules-load ${DESTDIR}/${PREFIX}/sbin/modules-load
 	install -m755 seedrng ${DESTDIR}/${PREFIX}/sbin/seedrng
 	install -m755 zzz ${DESTDIR}/${PREFIX}/sbin
+	install -m755 runit-analyze ${DESTDIR}/${PREFIX}/sbin
 	ln -sf zzz ${DESTDIR}/${PREFIX}/sbin/ZZZ
 	ln -sf halt ${DESTDIR}/${PREFIX}/sbin/poweroff
 	ln -sf halt ${DESTDIR}/${PREFIX}/sbin/reboot

runit-startuptime

@@ -0,0 +1,69 @@
+#!/bin/sh
+# vim: set ts=4 sw=4 et ft=awk:
+
+if [ -n "$1" ]; then
+    printf "Usage: runit-startuptime\n\nPrint a rough accounting of where time is spent during boot\n" >&2
+    exit 1
+fi
+
+dmesg -l debug | LANG=C.UTF-8 awk -F '[][ :]+' '
+BEGIN {
+    PROCINFO["sorted_in"] = "@ind_str_asc"
+    initramfs = 0
+    coresvtotal = 0
+    rclocal = 0
+    total = 0
+}
+
+function svbasename(file) {
+    sub(".*/", "", file)
+    sub(".sh$", "", file)
+    return file
+}
+
+$3 == "/init" {
+    initramfs = $2
+    next
+}
+
+$3 == "runit" {
+    if ($5 == "core") {
+        sv = svbasename($6)
+        if ($4 == "start") {
+            coresv[sv] = $2
+            if (coresvtotal == 0)
+                coresvtotal = $2
+        } else if ($4 == "finish") {
+            if ($6 != "") {
+                if (sv in coresv)
+                    coresv[sv] = $2 - coresv[sv]
+                else
+                    # /dev is not guaranteed until 00-pseudofs
+                    # so the first start message may not exist
+                    coresv[sv] = $2 - initramfs
+            } else
+                if (coresvtotal == 0)
+                    coresvtotal = $2 - initramfs
+                else
+                    coresvtotal = $2 - coresvtotal
+        }
+    } else if ($5 == "rclocal") {
+        if ($4 == "start")
+            rclocal = $2
+        else if ($4 == "finish")
+            rclocal = $2 - rclocal
+    } else if ($5 == "runsvdir")
+        total = $2
+    next
+}
+
+END {
+    if (NR > 2) {
+        printf "initramfs\t%0.3f s\n", initramfs
+        printf "core-services\t%0.3f s\n", coresvtotal
+        for (sv in coresv)
+            printf "  %-20s\t%0.3f s\n", sv, coresv[sv]
+        printf "rc.local\t%0.3f s\n", rclocal
+        printf "total\t\t%0.3f s\n", total
+    }
+}'

runit-startuptime.1

@@ -0,0 +1,40 @@
+.Dd September 4, 2024
+.Dt RUNIT-STARTUPTIME 1
+.Os
+.Sh NAME
+.Nm runit-startuptime
+.Nd Print a rough accounting of where time is spent during boot
+.Sh SYNOPSIS
+.Nm runit-startuptime
+.Sh DESCRIPTION
+Void's runit init scripts print messages to the kernel message buffer at startup,
+marking when some procedures start and finish.
+.Nm
+prints a rough accounting of where time is spent during boot using these messages.
+.Nm
+may require superuser privileges to read from dmesg.
+.Sh EXAMPLES
+.Bd -literal
+# runit-startuptime
+initramfs       0.646 s
+core-services   4.002 s
+  00-pseudofs           0.056 s
+  01-static-devnodes    1.178 s
+  02-kmods              0.027 s
+  02-udev               2.413 s
+  03-console-setup      0.096 s
+  03-filesystems        0.202 s
+  04-swap               0.004 s
+  05-misc               0.015 s
+  08-sysctl             0.008 s
+  20-screen             0.001 s
+  98-sbin-merge         0.000 s
+  99-cleanup            0.001 s
+rc.local        0.002 s
+total           7.952 s
+.Ed
+.Sh SEE ALSO
+.Xr runit-init 8
+.Sh AUTHOR
+.An classabbyamp ,
+.Mt [email protected] .