Always correct host settings instead of gating fixes behind flags

main.go

@@ -369,12 +369,10 @@ func main() {
 		rcvbuf   = flag.Int("rcvbuf", 64<<20, "SO_RCVBUFFORCE per rx socket")
 		txCPUs   = flag.String("txcpus", "", "comma-separated CPUs to pin tx workers to")
 		rxCPUs   = flag.String("rxcpus", "", "comma-separated CPUs to pin rx workers to")
-		tune     = flag.Bool("tune", true, "check host settings at startup and correct them; without this they are only reported")
 		governor = flag.String("governor", "performance", "required cpufreq governor")
 		coalesce = flag.Uint("coalesce-usecs", 25, "required fixed rx/tx coalesce usecs, with adaptive coalescing off")
 		rxRing   = flag.Uint("rx-ring", 8160, "required rx ring size, clamped to hardware maximum")
 		txRing   = flag.Uint("tx-ring", 4096, "required tx ring size, clamped to hardware maximum")
-		setRings = flag.Bool("set-rings", true, "allow ring resizing at startup, which resets the link")
 		color    = flag.String("color", "auto", "colored output: auto, always, never")
 	)
 	flag.Parse()
@@ -385,13 +383,11 @@ func main() {
 	}
 
 	tcfg := tuneConfig{
-		enabled:  *tune,
 		governor: *governor,
 		rxUsecs:  uint32(*coalesce),
 		txUsecs:  uint32(*coalesce),
 		rxRing:   uint32(*rxRing),
 		txRing:   uint32(*txRing),
-		setRings: *setRings,
 	}
 
 	if err := run(*aName, *bName, *sizesArg, *patArg, *fanout, *txCPUs, *rxCPUs,

tune.go

@@ -63,13 +63,11 @@ type ethtoolCoalesce struct {
 }
 
 type tuneConfig struct {
-	enabled  bool
 	governor string
 	rxUsecs  uint32
 	txUsecs  uint32
 	rxRing   uint32
 	txRing   uint32
-	setRings bool
 }
 
 type tuneResult struct {
@@ -128,13 +126,9 @@ func getCoalesce(fd int, ifname string) (ethtoolCoalesce, error) {
 	return ec, err
 }
 
-func governorPaths() ([]string, error) {
+func checkGovernor(want string) tuneResult {
-	return filepath.Glob("/sys/devices/system/cpu/cpu*/cpufreq/scaling_governor")
-}
-
-func checkGovernor(want string, fix bool) tuneResult {
 	res := tuneResult{item: "cpu governor"}
-	paths, err := governorPaths()
+	paths, err := filepath.Glob("/sys/devices/system/cpu/cpu*/cpufreq/scaling_governor")
 	if err != nil || len(paths) == 0 {
 		res.err = fmt.Errorf("no cpufreq governors found")
 		return res
@@ -161,11 +155,6 @@ func checkGovernor(want string, fix bool) tuneResult {
 	for k, v := range counts {
 		found = append(found, fmt.Sprintf("%s:%d", k, v))
 	}
-	if !fix {
-		res.err = fmt.Errorf("want %s, found %s", want, strings.Join(found, " "))
-		res.state = "not corrected"
-		return res
-	}
 	for _, p := range wrong {
 		if err := os.WriteFile(p, []byte(want), 0o644); err != nil {
 			res.err = err
@@ -178,7 +167,7 @@ func checkGovernor(want string, fix bool) tuneResult {
 	return res
 }
 
-func checkLinkUp(fd int, ifname string, fix bool) tuneResult {
+func checkLinkUp(fd int, ifname string) tuneResult {
 	res := tuneResult{item: ifname + " link up"}
 	var ifr flagsIfreq
 	copy(ifr.name[:], ifname)
@@ -186,18 +175,13 @@ func checkLinkUp(fd int, ifname string, fix bool) tuneResult {
 		uintptr(unix.SIOCGIFFLAGS), uintptr(unsafe.Pointer(&ifr)))
 	if errno != 0 {
 		res.err = errno
+		res.fatal = true
 		return res
 	}
 	if ifr.flags&unix.IFF_UP != 0 {
 		res.state = "up"
 		return res
 	}
-	if !fix {
-		res.err = fmt.Errorf("interface is down")
-		res.state = "not corrected"
-		res.fatal = true
-		return res
-	}
 	ifr.flags |= unix.IFF_UP
 	_, _, errno = unix.Syscall(unix.SYS_IOCTL, uintptr(fd),
 		uintptr(unix.SIOCSIFFLAGS), uintptr(unsafe.Pointer(&ifr)))
@@ -230,28 +214,22 @@ func checkCarrier(ifname string, wait time.Duration) tuneResult {
 	}
 }
 
-func checkCoalesce(fd int, ifname string, rxUsecs, txUsecs uint32, fix bool) tuneResult {
+func checkCoalesce(fd int, ifname string, rxUsecs, txUsecs uint32) tuneResult {
 	res := tuneResult{item: ifname + " coalesce"}
 	ec, err := getCoalesce(fd, ifname)
 	if err != nil {
 		res.err = err
 		return res
 	}
-	ok := ec.useAdaptiveRxCoalesce == 0 && ec.useAdaptiveTxCoalesce == 0 &&
-		ec.rxCoalesceUsecs == rxUsecs && ec.txCoalesceUsecs == txUsecs
 	desc := func(e ethtoolCoalesce) string {
 		return fmt.Sprintf("adaptive rx=%d tx=%d rx-usecs=%d tx-usecs=%d",
 			e.useAdaptiveRxCoalesce, e.useAdaptiveTxCoalesce, e.rxCoalesceUsecs, e.txCoalesceUsecs)
 	}
-	if ok {
+	if ec.useAdaptiveRxCoalesce == 0 && ec.useAdaptiveTxCoalesce == 0 &&
+		ec.rxCoalesceUsecs == rxUsecs && ec.txCoalesceUsecs == txUsecs {
 		res.state = desc(ec)
 		return res
 	}
-	if !fix {
-		res.err = fmt.Errorf("want adaptive off rx-usecs=%d tx-usecs=%d, have %s", rxUsecs, txUsecs, desc(ec))
-		res.state = "not corrected"
-		return res
-	}
 	was := desc(ec)
 	ec.cmd = unix.ETHTOOL_SCOALESCE
 	ec.useAdaptiveRxCoalesce = 0
@@ -268,7 +246,7 @@ func checkCoalesce(fd int, ifname string, rxUsecs, txUsecs uint32, fix bool) tun
 	return res
 }
 
-func checkRings(fd int, ifname string, rxWant, txWant uint32, fix bool) (tuneResult, bool) {
+func checkRings(fd int, ifname string, rxWant, txWant uint32) (tuneResult, bool) {
 	res := tuneResult{item: ifname + " rings"}
 	rp, err := getRings(fd, ifname)
 	if err != nil {
@@ -281,11 +259,6 @@ func checkRings(fd int, ifname string, rxWant, txWant uint32, fix bool) (tuneRes
 		res.state = fmt.Sprintf("rx=%d tx=%d", rp.rxPending, rp.txPending)
 		return res, false
 	}
-	if !fix {
-		res.err = fmt.Errorf("want rx=%d tx=%d, have rx=%d tx=%d", rx, tx, rp.rxPending, rp.txPending)
-		res.state = "not corrected"
-		return res, false
-	}
 	was := fmt.Sprintf("rx=%d tx=%d", rp.rxPending, rp.txPending)
 	rp.cmd = unix.ETHTOOL_SRINGPARAM
 	rp.rxPending = rx
@@ -296,7 +269,7 @@ func checkRings(fd int, ifname string, rxWant, txWant uint32, fix bool) (tuneRes
 		return res, false
 	}
 	res.fixed = true
-	res.state = fmt.Sprintf("was %s, now rx=%d tx=%d (link resets)", was, rx, tx)
+	res.state = fmt.Sprintf("was %s, now rx=%d tx=%d (link reset)", was, rx, tx)
 	return res, true
 }
 
@@ -324,57 +297,60 @@ func checkNoAddrs(ifname string) tuneResult {
 		res.state = "no routable addresses"
 		return res
 	}
-	res.err = fmt.Errorf("has %s, something is still configuring this interface", strings.Join(routable, ","))
+	res.err = fmt.Errorf("has %s; NetworkManager or DHCP is configuring this interface",
-	res.state = "not corrected"
+		strings.Join(routable, ","))
 	return res
 }
 
-func applyTuning(cfg tuneConfig, ifnames []string) []tuneResult {
+func withIoctlSocket(fn func(fd int) []tuneResult) []tuneResult {
 	fd, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, 0)
 	if err != nil {
-		return []tuneResult{{item: "ioctl socket", err: err}}
+		return []tuneResult{{item: "ioctl socket", err: err, fatal: true}}
 	}
 	defer unix.Close(fd)
+	return fn(fd)
+}
 
-	var out []tuneResult
+func applyTuning(cfg tuneConfig, ifnames []string) []tuneResult {
-	out = append(out, checkGovernor(cfg.governor, cfg.enabled))
+	return withIoctlSocket(func(fd int) []tuneResult {
-
+		out := []tuneResult{checkGovernor(cfg.governor)}
 		for _, ifname := range ifnames {
-		out = append(out, checkLinkUp(fd, ifname, cfg.enabled))
+			out = append(out, checkLinkUp(fd, ifname))
-		out = append(out, checkCoalesce(fd, ifname, cfg.rxUsecs, cfg.txUsecs, cfg.enabled))
+			out = append(out, checkCoalesce(fd, ifname, cfg.rxUsecs, cfg.txUsecs))
+
 			carrierWait := 3 * time.Second
-		if cfg.setRings {
+			r, reset := checkRings(fd, ifname, cfg.rxRing, cfg.txRing)
-			r, reset := checkRings(fd, ifname, cfg.rxRing, cfg.txRing, cfg.enabled)
 			out = append(out, r)
 			if reset {
 				carrierWait = 10 * time.Second
 			}
-		}
 			out = append(out, checkCarrier(ifname, carrierWait))
 			out = append(out, checkNoAddrs(ifname))
 		}
 		return out
+	})
 }
 
 func verifyTuning(cfg tuneConfig, ifnames []string) []tuneResult {
-	fd, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, 0)
+	return withIoctlSocket(func(fd int) []tuneResult {
-	if err != nil {
-		return []tuneResult{{item: "drift check", err: err}}
-	}
-	defer unix.Close(fd)
-
 		var drifted []tuneResult
-	if r := checkGovernor(cfg.governor, cfg.enabled); r.fixed || r.err != nil {
+		if r := checkGovernor(cfg.governor); r.fixed || r.err != nil {
 			drifted = append(drifted, r)
 		}
 		for _, ifname := range ifnames {
-		if r := checkCoalesce(fd, ifname, cfg.rxUsecs, cfg.txUsecs, cfg.enabled); r.fixed || r.err != nil {
+			if r := checkCoalesce(fd, ifname, cfg.rxUsecs, cfg.txUsecs); r.fixed || r.err != nil {
 				drifted = append(drifted, r)
 			}
-		if r, _ := checkRings(fd, ifname, cfg.rxRing, cfg.txRing, false); r.err != nil {
+			r, reset := checkRings(fd, ifname, cfg.rxRing, cfg.txRing)
-			r.state = "left alone, resizing would reset the link"
+			if r.fixed || r.err != nil {
 				drifted = append(drifted, r)
 			}
+			if reset {
+				if c := checkCarrier(ifname, 10*time.Second); c.err != nil {
+					drifted = append(drifted, c)
+				}
+			}
 		}
 		return drifted
+	})
 }