From a31c186142b97b43c1b0c2fdcc5e1f950cc40680 Mon Sep 17 00:00:00 2001
From: ETWen <eric441151893@gmail.com>
Date: Wed, 26 Aug 2026 09:53:20 +0800
Subject: [PATCH] feat(mgmt): Ping both NICs at once, and stop counting ARP as
 loss

The bench run reported FAIL=3 with no NIC errors and no drops. All three
failures were on eth1 and all three were missing exactly icmp_seq=1,
with the other nine replies present and sub-millisecond. That is
neighbour resolution: once the ARP entry for the target expires, the
first echo request is spent resolving it and ping counts it as loss.
Rounds sat about 24 s apart, right on the edge of the default reachable
time, so it happened on some rounds and not others.

mgmt_ping_monitor.sh V3.0.0:

- One discarded ping per NIC before the measured run resolves ARP, so
  MAX_LOSS_PCT can stay at 0 and a FAIL means a real drop. Raising the
  threshold instead would have hidden genuine single-packet loss, and a
  longer settle would not help -- nothing triggers ARP until the ping.
- Both NICs now ping at the same time and keep accumulating until
  stopped, rather than alternating fixed bursts. Each writes its own raw
  capture.
- `stop` sends SIGINT rather than SIGTERM, because ping prints its
  statistics block on interrupt and that block is what the report
  parses, then renders into the log: the last TAIL_LINES entries per
  NIC, each one's statistics and verdict, and `ip -s link show` for both
  interfaces.
- `-D -O` are on by default so every line carries a timestamp and a
  request that got no reply is visible in the tail instead of merely
  absent. Clear PING_EXTRA_OPTS if the platform's ping rejects them.

Since the script no longer re-execs itself to daemonise, `bash
mgmt_ping_monitor.sh start` works without the execute bit.

.gitignore: the new *.raw / *.pid / *.state runtime files were outside
the *.log rule and would have been committed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014RetWKFZFG1ZHcitQAyhwM
---
 .gitignore                                    |   5 +
 src/Script_ABC_Blanton/1_Blanton_Script_A.ttl |   4 +
 .../Blanton_Script/mgmt_ping_monitor.sh       | 594 ++++++++----------
 3 files changed, 276 insertions(+), 327 deletions(-)

diff --git a/.gitignore b/.gitignore
index 8a1fadb..03cda2a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,6 +12,11 @@ For_AI/
 !**/logs/.gitkeep
 !**/Logs/.gitkeep
 
+# monitor 腳本的執行期產物（原始擷取、pid、狀態）
+*.raw
+*.pid
+*.state
+
 # 打包輸出：產出不進 git，打包工具本身要進
 publish/*
 !publish/.gitkeep
diff --git a/src/Script_ABC_Blanton/1_Blanton_Script_A.ttl b/src/Script_ABC_Blanton/1_Blanton_Script_A.ttl
index 4e604d7..3392895 100644
--- a/src/Script_ABC_Blanton/1_Blanton_Script_A.ttl
+++ b/src/Script_ABC_Blanton/1_Blanton_Script_A.ttl
@@ -51,6 +51,10 @@
 ;                       ScriptB                                         USB stress uses the detected node, not a hard-coded /dev/sda1
 ;                       ScriptB                                         DDR memtester runs continuously (drop the 100-pass limit)
 ;                       ScriptC                                         Move bgctl reset --yes after the USB archive
+;                       Blanton_Script/mgmt_ping_monitor.sh             V3.0.0 - both NICs ping simultaneously, accumulating
+;                                                                         + ARP warm-up so a stale neighbour entry is not counted as loss
+;                                                                         + stop renders last-N per NIC, stats, and both ip -s link show
+;                       .gitignore                                      Ignore monitor *.raw / *.pid / *.state
 ; =============================================================================
 include "config.ttl"
 
diff --git a/src/Script_ABC_Blanton/Blanton_Script/mgmt_ping_monitor.sh b/src/Script_ABC_Blanton/Blanton_Script/mgmt_ping_monitor.sh
index 7ed96e3..c6acc99 100644
--- a/src/Script_ABC_Blanton/Blanton_Script/mgmt_ping_monitor.sh
+++ b/src/Script_ABC_Blanton/Blanton_Script/mgmt_ping_monitor.sh
@@ -2,48 +2,41 @@
 ###############################################################################
 # mgmt_ping_monitor.sh
 #
-# Version : V1.0.0
+# Version : V3.0.0
 # Author  : ETWen
-# Date    : 20260824
+# Date    : 20260826
 #
-# Purpose : Exercise both management NICs and ping each one's own target,
-#           appending everything to a rotating log. One round is
+# Purpose : Ping from BOTH management NICs at the same time, continuously, and
+#           keep accumulating until stopped:
 #
-#               10G (eth0) : ip link up + address/route replace -> settle
-#                            -> ping N x TARGET_10G -> ip -s link show
-#               1G  (eth1) : ip link up + address/route replace -> settle
-#                            -> ping N x TARGET_1G  -> ip -s link show
+#               10G (eth0) -> TARGET_10G
+#               1G  (eth1) -> TARGET_1G
 #
-#           Designed to run detached in the background, same sub-commands as
-#           bmc_monitor.sh: start/stop/status/fg/tail/clear.
+#           `stop` renders a report into the log: the last TAIL_LINES entries
+#           per NIC, each one's ping statistics and verdict, then
+#           `ip -s link show` for both interfaces.
 #
-# Notes   : - Both NICs are brought up and LEFT up. Addresses and default
-#             routes are applied with iproute2 `replace`, which is idempotent:
-#             re-running a round does not stack duplicate addresses or routes.
-#           - The default routes carry different metrics (100 / 200), so the
-#             lower one wins for off-subnet traffic. They do NOT decide which
-#             NIC a ping leaves by: `ping -I <iface>` binds to the device.
-#           - !! SAME-SUBNET WARNING !! With both NICs up on one subnet the
-#             target ARPs for the address and Linux may answer from either
-#             NIC, so replies can arrive on the wrong one and the result is
-#             not attributable. ARP_STRICT=1 sets arp_ignore/arp_announce to
-#             stop that. Leave it on unless the two NICs are on separate
-#             subnets, as in the iproute2 example this was modelled on.
-#           - Each leg logs `ip -s link show <iface>` and the TX/RX packet
-#             delta across the burst, which is the direct evidence of which
-#             NIC actually carried the traffic.
-#           - The first pings after bringing a link up are lost to ARP, not to
-#             the link: a bench capture showed 4x "Destination Host
-#             Unreachable" on the first burst and 0% loss on the very next
-#             one. LINK_SETTLE_SEC absorbs that; it is not packet loss.
+# Notes   : - Both NICs are configured with iproute2 `replace`, which is
+#             idempotent, and both are left up. On a shared subnet the target's
+#             ARP can be answered by either NIC, so ARP_STRICT keeps each one
+#             to its own address.
+#           - ARP WARM-UP: the first packet after a neighbour entry expires is
+#             spent resolving ARP and is counted as loss. On the bench this
+#             produced three FAILs whose only missing packet was icmp_seq=1,
+#             every time, with zero NIC errors or drops. One discarded ping
+#             before the measured run removes that artefact, which is what lets
+#             MAX_LOSS_PCT stay at 0 and still mean something.
+#           - MANAGEMENT CONNECTIVITY IS IN USE while this runs. Drive it from
+#             the serial console.
 #
 # Version History
-# V1.0.0     20260824    Initial Version
-# V2.0.0     20260824    Switch from ifconfig to iproute2 (ip link / address
-#                        replace / route replace with per-NIC metric). Both
-#                        NICs now stay up -- no link down between legs. Add
-#                        `ip -s link show` per leg with a TX/RX delta, and
-#                        ARP_STRICT for the same-subnet case.
+# V1.0.0     20260824    Initial Version (ifconfig, one NIC at a time)
+# V2.0.0     20260824    iproute2; both NICs stay up; per-NIC target;
+#                        ip -s link show + TX/RX delta per leg
+# V3.0.0     20260826    Both NICs ping SIMULTANEOUSLY and continuously instead
+#                        of alternating fixed bursts. Add the ARP warm-up.
+#                        `stop` renders last-N per NIC + statistics + both
+#                        ip -s link outputs into the log.
 ###############################################################################
 
 set -u
@@ -63,149 +56,67 @@ METRIC_10G=100                 # lower metric wins for off-subnet traffic
 # --- 1G management port ---
 IF_1G="eth1"
 IP_1G="192.168.1.101"
-TARGET_1G="192.168.1.31"       # host this NIC pings
+TARGET_1G="192.168.1.31"
 PLEN_1G=24
 GW_1G=""
 METRIC_1G=200
 
 # --- ping ---
-PING_COUNT=10                  # echo requests per leg
-MAX_LOSS_PCT=0                 # loss above this marks the leg FAIL
+PING_INTERVAL_SEC=1            # seconds between echo requests (ping -i)
+MAX_LOSS_PCT=0                 # loss above this marks the NIC FAIL
+TAIL_LINES=20                  # how many recent entries per NIC the report shows
 
-# Both NICs stay up. If they share a subnet the target's ARP can be answered
-# by either one, so a reply may arrive on the NIC that did not send. Setting
-# this applies arp_ignore=1 / arp_announce=2 to both, which keeps each NIC to
-# its own address. RAM only -- reverts on reboot. Set 0 for separate subnets.
+# Extra ping flags. -D timestamps every line, -O prints a marker for a request
+# that got no reply, so a drop is visible in the tail instead of just missing.
+# Clear this if the platform's ping does not accept them.
+PING_EXTRA_OPTS="-D -O"
+
+# One discarded ping per NIC before the measured run, to resolve ARP. Without
+# it the first packet of the run is lost to neighbour resolution and looks
+# exactly like a link fault. 0 disables.
+ARP_WARMUP=1
+ARP_WARMUP_TIMEOUT=2           # seconds to wait for the warm-up reply
+
+# Both NICs stay up. If they share a subnet the target's ARP can be answered by
+# either one, so a reply may arrive on the NIC that did not send. This applies
+# arp_ignore=1 / arp_announce=2 to both. RAM only -- reverts on reboot.
 ARP_STRICT=1
 
-# Prefix for the ip commands; empty because the daemon already runs as root.
+# Prefix for the ip commands; empty because this already runs as root.
 SUDO=""
 
-# Seconds to wait after bringing a link up before pinging, so ARP is resolved
-# and the PHY has finished autoneg. The bench needed a few seconds on the 1G.
+# Seconds to wait after bringing a link up before pinging.
 LINK_SETTLE_SEC=5
 
-# Seconds between rounds (0 = start the next round immediately)
-INTERVAL_SEC=10
-
-# Per-ping-burst timeout in seconds; stops a wedged ping from freezing the
-# loop. 0 disables. Must exceed PING_COUNT (one packet per second).
-PING_TIMEOUT_SEC=60
-
-# Stop after this many rounds. 0 = run until stopped manually.
-MAX_ROUNDS=0
-
 # Logging
-LOG_DIR=""                      # empty = <script directory>/log
+LOG_DIR=""                     # empty = <script directory>/log
 LOG_NAME="mgmt_ping.log"
-MAX_LOG_SIZE_MB=100             # rotate above this size; 0 = never rotate
-MAX_LOG_KEEP=5                  # keep .1 .. .N
 
 # What `start` does with the log left behind by the previous run:
-#   new     = begin with an empty log; previous content and rotated copies are
-#             discarded (default -- one run, one log)
-#   archive = rename the previous log to <log>.YYYYmmdd-HHMMSS, then begin empty
-#   append  = keep appending to the existing log
+#   new     = discard it (default -- one run, one log)
+#   archive = rename it to <log>.YYYYmmdd-HHMMSS first
+#   append  = keep it
 START_LOG_MODE="new"
 
 ###############################################################################
 # Internal
 ###############################################################################
 SCRIPT_NAME="$(basename -- "${BASH_SOURCE[0]}")"
-SCRIPT_PATH="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)/${SCRIPT_NAME}"
-[ -n "${LOG_DIR}" ] || LOG_DIR="$(dirname -- "${SCRIPT_PATH}")/log"
-LOG_FILE="${LOG_DIR}/${LOG_NAME}"
-PID_FILE="${LOG_DIR}/${LOG_NAME%.log}.pid"
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+[ -n "${LOG_DIR}" ] || LOG_DIR="${SCRIPT_DIR}/log"
 
-LOG_TO_FILE=0
-STOP=0
-SLEEP_PID=""
+LOG_FILE="${LOG_DIR}/${LOG_NAME}"
+BASE="${LOG_DIR}/${LOG_NAME%.log}"
+PID_FILE="${BASE}.pid"
+STATE_FILE="${BASE}.state"
+RAW_10G="${BASE}_${IF_10G}.raw"
+RAW_1G="${BASE}_${IF_1G}.raw"
 
 ts()  { date '+%Y-%m-%d %H:%M:%S'; }
 die() { printf '[ERROR] %s\n' "$*" >&2; exit 1; }
 
-on_signal() {
-    STOP=1
-    [ -n "${SLEEP_PID}" ] && kill "${SLEEP_PID}" 2>/dev/null
-}
-
-interruptible_sleep() {
-    local sec="$1"
-    [ "${sec}" -gt 0 ] 2>/dev/null || return 0
-    sleep "${sec}" &
-    SLEEP_PID=$!
-    wait "${SLEEP_PID}" 2>/dev/null
-    SLEEP_PID=""
-}
-
-is_running() {
-    local pid
-    [ -f "${PID_FILE}" ] || return 1
-    pid="$(cat "${PID_FILE}" 2>/dev/null)"
-    [[ "${pid}" =~ ^[0-9]+$ ]] || return 1
-    kill -0 "${pid}" 2>/dev/null || return 1
-    grep -qa "${SCRIPT_NAME}" "/proc/${pid}/cmdline" 2>/dev/null || return 1
-    printf '%s' "${pid}"
-    return 0
-}
-
-rotate_log_if_needed() {
-    local max_bytes size i
-    [ "${LOG_TO_FILE}" -eq 1 ] || return 0
-    [ "${MAX_LOG_SIZE_MB}" -gt 0 ] || return 0
-    [ -f "${LOG_FILE}" ] || return 0
-
-    max_bytes=$(( MAX_LOG_SIZE_MB * 1024 * 1024 ))
-    size="$(stat -c %s "${LOG_FILE}" 2>/dev/null || echo 0)"
-    [ "${size}" -ge "${max_bytes}" ] || return 0
-
-    for (( i = MAX_LOG_KEEP - 1; i >= 1; i-- )); do
-        [ -f "${LOG_FILE}.${i}" ] && mv -f "${LOG_FILE}.${i}" "${LOG_FILE}.$(( i + 1 ))"
-    done
-    mv -f "${LOG_FILE}" "${LOG_FILE}.1"
-    exec >>"${LOG_FILE}" 2>&1
-    printf '[%s] INFO : log rotated at %s MB\n' "$(ts)" "${MAX_LOG_SIZE_MB}"
-}
-
-remove_rotated_logs() {
-    local i
-    for (( i = 1; i <= MAX_LOG_KEEP + 1; i++ )); do
-        rm -f "${LOG_FILE}.${i}"
-    done
-}
-
-prepare_log_on_start() {
-    local stamp
-    case "${START_LOG_MODE}" in
-        append)
-            return 0
-            ;;
-        archive)
-            if [ -s "${LOG_FILE}" ]; then
-                stamp="$(date '+%Y%m%d-%H%M%S')"
-                mv -f "${LOG_FILE}" "${LOG_FILE}.${stamp}" \
-                    || die "cannot archive ${LOG_FILE}"
-                printf 'previous log archived: %s.%s\n' "${LOG_FILE}" "${stamp}"
-            fi
-            remove_rotated_logs
-            ;;
-        new)
-            # Truncate rather than unlink: the inode is preserved, so a tail -f
-            # that is already attached keeps following the new run.
-            if [ -f "${LOG_FILE}" ]; then
-                : > "${LOG_FILE}" || die "cannot truncate ${LOG_FILE}"
-            fi
-            remove_rotated_logs
-            ;;
-        *)
-            die "invalid START_LOG_MODE: ${START_LOG_MODE}"
-            ;;
-    esac
-}
-
-# Cumulative "<rx_packets> <tx_packets>" for an interface, from ip -s link.
-# The numbers sit on the line after each RX:/TX: header, and the column order
-# is "bytes packets errors ..." -- so packets is $2, not $1.
+# "<rx_packets> <tx_packets>" for an interface. ip -s link orders the columns
+# "bytes packets errors ...", so packets is $2, not $1.
 if_counters() {
     ${SUDO} ip -s link show "$1" 2>/dev/null | awk '
         /RX:/ { getline; rx = $2 }
@@ -213,88 +124,18 @@ if_counters() {
         END   { printf "%s %s", (rx == "" ? 0 : rx), (tx == "" ? 0 : tx) }'
 }
 
-# Bring the NIC up and (re)apply its address and default route. `replace` is
-# idempotent, so repeated rounds do not stack duplicates.
+# Bring the NIC up and (re)apply its address and default route.
 setup_iface() {
     local iface="$1" ipaddr="$2" plen="$3" gw="$4" metric="$5"
-
-    ${SUDO} ip link set "${iface}" up 2>&1                                  || return 1
-    ${SUDO} ip address replace "${ipaddr}/${plen}" dev "${iface}" 2>&1      || return 1
+    ${SUDO} ip link set "${iface}" up 2>&1                             || return 1
+    ${SUDO} ip address replace "${ipaddr}/${plen}" dev "${iface}" 2>&1 || return 1
     if [ -n "${gw}" ]; then
         ${SUDO} ip route replace default via "${gw}" dev "${iface}" \
-                metric "${metric}" 2>&1                                     || return 1
+                metric "${metric}" 2>&1                                || return 1
     fi
     return 0
 }
 
-# One leg: configure <if>, settle, ping its own target, report. The NIC is
-# LEFT UP -- nothing is brought down between legs.
-# Usage: ping_leg <label> <if> <ip> <plen> <gw> <metric> <target>
-ping_leg() {
-    local label="$1" iface="$2" ipaddr="$3" plen="$4" gw="$5" metric="$6" target="$7"
-    local out rc tx rx loss avg verdict
-    local c0 c1 rx0 tx0 rx1 tx1 drx dtx
-
-    printf -- '----- [%s] %s : %s (%s/%s) -> %s -----\n' \
-              "$(ts)" "${label}" "${iface}" "${ipaddr}" "${plen}" "${target}"
-
-    if ! setup_iface "${iface}" "${ipaddr}" "${plen}" "${gw}" "${metric}"; then
-        printf '[%s] FAIL : cannot configure %s\n\n' "$(ts)" "${iface}"
-        return 1
-    fi
-    interruptible_sleep "${LINK_SETTLE_SEC}"
-    [ "${STOP}" -eq 0 ] || return 1
-
-    c0="$(if_counters "${iface}")"; rx0="${c0% *}"; tx0="${c0#* }"
-
-    if [ "${PING_TIMEOUT_SEC}" -gt 0 ]; then
-        out="$(timeout "${PING_TIMEOUT_SEC}" ping -I "${iface}" -c "${PING_COUNT}" "${target}" 2>&1)"
-    else
-        out="$(ping -I "${iface}" -c "${PING_COUNT}" "${target}" 2>&1)"
-    fi
-    rc=$?
-    printf '%s\n' "${out}"
-
-    c1="$(if_counters "${iface}")"; rx1="${c1% *}"; tx1="${c1#* }"
-    drx=$(( rx1 - rx0 )); dtx=$(( tx1 - tx0 ))
-
-    printf -- '--- ip -s link show %s ---\n' "${iface}"
-    ${SUDO} ip -s link show "${iface}" 2>&1
-
-    # "10 packets transmitted, 10 received, 0% packet loss"
-    tx="$(printf '%s' "${out}"   | sed -n 's/^\([0-9]\+\) packets transmitted.*/\1/p'   | tail -1)"
-    rx="$(printf '%s' "${out}"   | sed -n 's/.*[, ]\([0-9]\+\) received.*/\1/p'         | tail -1)"
-    loss="$(printf '%s' "${out}" | sed -n 's/.*[, ]\([0-9]\+\)% packet loss.*/\1/p'     | tail -1)"
-    # "rtt min/avg/max/mdev = 1.044/1.743/2.387/0.437 ms"
-    avg="$(printf '%s' "${out}"  | sed -n 's|.*= [0-9.]*/\([0-9.]*\)/.*|\1|p'           | tail -1)"
-
-    [ -n "${tx}" ]   || tx=0
-    [ -n "${rx}" ]   || rx=0
-    [ -n "${loss}" ] || loss=100
-    [ -n "${avg}" ]  || avg="-"
-
-    if [ "${rc}" -eq 124 ]; then
-        verdict="FAIL(timeout)"
-    elif [ "${loss}" -le "${MAX_LOSS_PCT}" ]; then
-        verdict="PASS"
-    else
-        verdict="FAIL"
-    fi
-
-    # one greppable line per leg: grep RESULT <log>
-    # nic_tx/nic_rx are this interface's own counter delta across the burst --
-    # if they stay near zero while the ping succeeded, the traffic went out a
-    # different NIC and the result is not attributable to this one.
-    printf '[%s] RESULT %-3s %-6s -> %-15s tx=%s rx=%s loss=%s%% rtt_avg=%sms nic_tx=%s nic_rx=%s %s\n\n' \
-           "$(ts)" "${label}" "${iface}" "${target}" "${tx}" "${rx}" "${loss}" "${avg}" \
-           "${dtx}" "${drx}" "${verdict}"
-
-    [ "${verdict}" = "PASS" ]
-}
-
-# arp_ignore=1 : answer ARP only for addresses configured on the incoming NIC
-# arp_announce=2: pick the source address from the outgoing NIC's own subnet
-# Both are RAM-only sysctls and revert on reboot.
 apply_arp_strict() {
     local i
     [ "${ARP_STRICT}" -eq 1 ] || return 0
@@ -302,143 +143,245 @@ apply_arp_strict() {
         ${SUDO} sysctl -qw "net.ipv4.conf.${i}.arp_ignore=1"   2>/dev/null
         ${SUDO} sysctl -qw "net.ipv4.conf.${i}.arp_announce=2" 2>/dev/null
     done
-    printf '[%s] INFO : arp_ignore=1 arp_announce=2 applied to %s,%s\n' \
-           "$(ts)" "${IF_10G}" "${IF_1G}"
 }
 
-main_loop() {
-    local round=0 pass=0 fail=0
+# Resolve the neighbour so the measured run does not spend its first packet on
+# ARP. Result is deliberately discarded.
+arp_warmup() {
+    local iface="$1" target="$2"
+    [ "${ARP_WARMUP}" -eq 1 ] || return 0
+    ping -I "${iface}" -c 1 -W "${ARP_WARMUP_TIMEOUT}" "${target}" >/dev/null 2>&1
+    return 0
+}
 
-    command -v ip   >/dev/null 2>&1 || die "ip (iproute2) not found"
-    command -v ping >/dev/null 2>&1 || die "ping not found"
-    [ "${PING_COUNT}" -gt 0 ] 2>/dev/null || die "PING_COUNT must be > 0"
+# echo "pid_10g pid_1g" and return 0 when both are alive
+is_running() {
+    local p0 p1
+    [ -f "${PID_FILE}" ] || return 1
+    p0="$(sed -n '1p' "${PID_FILE}" 2>/dev/null)"
+    p1="$(sed -n '2p' "${PID_FILE}" 2>/dev/null)"
+    [[ "${p0}" =~ ^[0-9]+$ ]] || return 1
+    [[ "${p1}" =~ ^[0-9]+$ ]] || return 1
+    kill -0 "${p0}" 2>/dev/null || kill -0 "${p1}" 2>/dev/null || return 1
+    printf '%s %s' "${p0}" "${p1}"
+    return 0
+}
 
-    trap on_signal INT TERM
+###############################################################################
+# Report
+###############################################################################
 
-    printf '#############################################################\n'
-    printf '[%s] START: pid=%d count=%d settle=%ds interval=%ds\n' \
-           "$(ts)" "$$" "${PING_COUNT}" "${LINK_SETTLE_SEC}" "${INTERVAL_SEC}"
-    printf '[%s]        10G %s %s/%s -> %s  (metric %s)\n' \
-           "$(ts)" "${IF_10G}" "${IP_10G}" "${PLEN_10G}" "${TARGET_10G}" "${METRIC_10G}"
-    printf '[%s]        1G  %s %s/%s -> %s  (metric %s)\n' \
-           "$(ts)" "${IF_1G}" "${IP_1G}" "${PLEN_1G}" "${TARGET_1G}" "${METRIC_1G}"
-    printf '#############################################################\n'
+# The recent entries for one NIC: replies and, thanks to -O, the requests that
+# got none.
+tail_entries() {
+    grep -aE 'bytes from|no answer|Unreachable|Time to live' "$1" 2>/dev/null \
+        | tail -n "${TAIL_LINES}"
+}
 
-    apply_arp_strict
+# The trailing "--- x ping statistics ---" block.
+stats_block() {
+    sed -n '/ping statistics ---/,$p' "$1" 2>/dev/null
+}
 
-    while [ "${STOP}" -eq 0 ]; do
-        round=$(( round + 1 ))
-        printf -- '---------- ROUND %d @ %s ----------\n' "${round}" "$(ts)"
+# render_leg <label> <iface> <target> <raw> <rx0> <tx0>
+render_leg() {
+    local label="$1" iface="$2" target="$3" raw="$4" rx0="$5" tx0="$6"
+    local st tx rx loss avg verdict c1 rx1 tx1 drx dtx
 
-        if ping_leg "10G" "${IF_10G}" "${IP_10G}" "${PLEN_10G}" "${GW_10G}" \
-                    "${METRIC_10G}" "${TARGET_10G}"; then
-            pass=$(( pass + 1 )); else fail=$(( fail + 1 ))
-        fi
-        [ "${STOP}" -eq 0 ] || break
+    printf -- '----- %s : %s -> %s : last %s entries -----\n' \
+              "${label}" "${iface}" "${target}" "${TAIL_LINES}"
+    tail_entries "${raw}"
+    printf '\n'
+    st="$(stats_block "${raw}")"
+    printf '%s\n' "${st}"
 
-        if ping_leg "1G" "${IF_1G}" "${IP_1G}" "${PLEN_1G}" "${GW_1G}" \
-                    "${METRIC_1G}" "${TARGET_1G}"; then
-            pass=$(( pass + 1 )); else fail=$(( fail + 1 ))
-        fi
+    tx="$(printf '%s' "${st}"   | sed -n 's/^\([0-9]\+\) packets transmitted.*/\1/p'   | tail -1)"
+    rx="$(printf '%s' "${st}"   | sed -n 's/.*[, ]\([0-9]\+\) received.*/\1/p'         | tail -1)"
+    loss="$(printf '%s' "${st}" | sed -n 's/.*[, ]\([0-9]\+\)% packet loss.*/\1/p'     | tail -1)"
+    avg="$(printf '%s' "${st}"  | sed -n 's|.*= [0-9.]*/\([0-9.]*\)/.*|\1|p'           | tail -1)"
+    [ -n "${tx}" ]   || tx=0
+    [ -n "${rx}" ]   || rx=0
+    [ -n "${loss}" ] || loss=100
+    [ -n "${avg}" ]  || avg="-"
 
-        rotate_log_if_needed
+    c1="$(if_counters "${iface}")"; rx1="${c1% *}"; tx1="${c1#* }"
+    drx=$(( rx1 - rx0 )); dtx=$(( tx1 - tx0 ))
 
-        if [ "${MAX_ROUNDS}" -gt 0 ] && [ "${round}" -ge "${MAX_ROUNDS}" ]; then
-            break
-        fi
-        [ "${STOP}" -eq 0 ] && interruptible_sleep "${INTERVAL_SEC}"
-    done
+    if [ "${loss}" -le "${MAX_LOSS_PCT}" ] && [ "${tx}" -gt 0 ]; then
+        verdict="PASS"
+    else
+        verdict="FAIL"
+    fi
 
-    printf '[%s] STOP : pid=%d after %d round(s), legs PASS=%d FAIL=%d\n' \
-           "$(ts)" "$$" "${round}" "${pass}" "${fail}"
+    # nic_tx/nic_rx are this interface's own counter delta over the whole run.
+    # A pass with nic_tx near zero means the traffic left on the other NIC.
+    printf '[%s] RESULT %-3s %-6s -> %-15s tx=%s rx=%s loss=%s%% rtt_avg=%sms nic_tx=%s nic_rx=%s %s\n\n' \
+           "$(ts)" "${label}" "${iface}" "${target}" "${tx}" "${rx}" "${loss}" "${avg}" \
+           "${dtx}" "${drx}" "${verdict}"
+}
+
+write_report() {
+    local rx0_10g tx0_10g rx0_1g tx0_1g started
+    started="$(sed -n '1p' "${STATE_FILE}" 2>/dev/null)"
+    rx0_10g="$(sed -n '2p' "${STATE_FILE}" 2>/dev/null)"; rx0_10g="${rx0_10g:-0}"
+    tx0_10g="$(sed -n '3p' "${STATE_FILE}" 2>/dev/null)"; tx0_10g="${tx0_10g:-0}"
+    rx0_1g="$(sed -n '4p' "${STATE_FILE}" 2>/dev/null)";  rx0_1g="${rx0_1g:-0}"
+    tx0_1g="$(sed -n '5p' "${STATE_FILE}" 2>/dev/null)";  tx0_1g="${tx0_1g:-0}"
+
+    {
+        printf '#############################################################\n'
+        printf '[%s] mgmt ping report\n' "$(ts)"
+        printf '  started : %s\n' "${started:-unknown}"
+        printf '  stopped : %s\n' "$(ts)"
+        printf '  10G     : %s %s/%s -> %s (metric %s)\n' \
+               "${IF_10G}" "${IP_10G}" "${PLEN_10G}" "${TARGET_10G}" "${METRIC_10G}"
+        printf '  1G      : %s %s/%s -> %s (metric %s)\n' \
+               "${IF_1G}" "${IP_1G}" "${PLEN_1G}" "${TARGET_1G}" "${METRIC_1G}"
+        printf '  ping    : -i %s %s, max loss %s%%\n' \
+               "${PING_INTERVAL_SEC}" "${PING_EXTRA_OPTS}" "${MAX_LOSS_PCT}"
+        printf '#############################################################\n\n'
+
+        render_leg "10G" "${IF_10G}" "${TARGET_10G}" "${RAW_10G}" "${rx0_10g}" "${tx0_10g}"
+        render_leg "1G"  "${IF_1G}"  "${TARGET_1G}"  "${RAW_1G}"  "${rx0_1g}"  "${tx0_1g}"
+
+        printf -- '--- ip -s link show %s ---\n' "${IF_10G}"
+        ${SUDO} ip -s link show "${IF_10G}" 2>&1
+        printf '\n'
+        printf -- '--- ip -s link show %s ---\n' "${IF_1G}"
+        ${SUDO} ip -s link show "${IF_1G}" 2>&1
+    } >> "${LOG_FILE}"
 }
 
 ###############################################################################
 # Sub-commands
 ###############################################################################
-do_start() {
-    local pid
-    pid="$(is_running)" && die "already running (pid=${pid})"
-    mkdir -p "${LOG_DIR}" || die "cannot create ${LOG_DIR}"
-    prepare_log_on_start
-
-    if command -v setsid >/dev/null 2>&1; then
-        setsid "${SCRIPT_PATH}" __daemon >/dev/null 2>&1 &
-    else
-        nohup "${SCRIPT_PATH}" __daemon >/dev/null 2>&1 &
-        disown 2>/dev/null
-    fi
-
-    sleep 1
-    pid="$(is_running)" || die "start failed, check ${LOG_FILE}"
-    printf 'started (pid=%s)\nlog: %s\n' "${pid}" "${LOG_FILE}"
+prepare_log_on_start() {
+    local stamp
+    case "${START_LOG_MODE}" in
+        append) return 0 ;;
+        archive)
+            if [ -s "${LOG_FILE}" ]; then
+                stamp="$(date '+%Y%m%d-%H%M%S')"
+                mv -f "${LOG_FILE}" "${LOG_FILE}.${stamp}" || die "cannot archive ${LOG_FILE}"
+                printf 'previous log archived: %s.%s\n' "${LOG_FILE}" "${stamp}"
+            fi
+            ;;
+        new)
+            # Truncate rather than unlink, so a tail -f already attached keeps
+            # following the new run.
+            [ -f "${LOG_FILE}" ] && { : > "${LOG_FILE}" || die "cannot truncate ${LOG_FILE}"; }
+            ;;
+        *) die "invalid START_LOG_MODE: ${START_LOG_MODE}" ;;
+    esac
 }
 
-do_daemon() {
+do_start() {
+    local pids p0 p1 c
+
+    pids="$(is_running)" && die "already running (pids=${pids})"
+
+    command -v ip   >/dev/null 2>&1 || die "ip (iproute2) not found"
+    command -v ping >/dev/null 2>&1 || die "ping not found"
+
     mkdir -p "${LOG_DIR}" || die "cannot create ${LOG_DIR}"
-    LOG_TO_FILE=1
-    exec >>"${LOG_FILE}" 2>&1
-    printf '%d\n' "$$" > "${PID_FILE}"
-    trap 'rm -f "${PID_FILE}"' EXIT
-    main_loop
+    prepare_log_on_start
+    : > "${RAW_10G}"
+    : > "${RAW_1G}"
+
+    setup_iface "${IF_10G}" "${IP_10G}" "${PLEN_10G}" "${GW_10G}" "${METRIC_10G}" \
+        || die "cannot configure ${IF_10G}"
+    setup_iface "${IF_1G}"  "${IP_1G}"  "${PLEN_1G}"  "${GW_1G}"  "${METRIC_1G}" \
+        || die "cannot configure ${IF_1G}"
+    apply_arp_strict
+    sleep "${LINK_SETTLE_SEC}"
+
+    # Spend the ARP resolution here, not on the first measured packet.
+    arp_warmup "${IF_10G}" "${TARGET_10G}"
+    arp_warmup "${IF_1G}"  "${TARGET_1G}"
+
+    # Counter baseline, taken after the warm-up so its packets are excluded.
+    { c="$(if_counters "${IF_10G}")"
+      printf '%s\n%s\n%s\n' "$(ts)" "${c% *}" "${c#* }"
+      c="$(if_counters "${IF_1G}")"
+      printf '%s\n%s\n' "${c% *}" "${c#* }"
+    } > "${STATE_FILE}"
+
+    # Both NICs ping at the same time and keep accumulating until stopped.
+    nohup ping -I "${IF_10G}" -i "${PING_INTERVAL_SEC}" ${PING_EXTRA_OPTS} \
+          "${TARGET_10G}" >> "${RAW_10G}" 2>&1 &
+    p0=$!
+    nohup ping -I "${IF_1G}"  -i "${PING_INTERVAL_SEC}" ${PING_EXTRA_OPTS} \
+          "${TARGET_1G}"  >> "${RAW_1G}"  2>&1 &
+    p1=$!
+    disown "${p0}" 2>/dev/null
+    disown "${p1}" 2>/dev/null
+    printf '%s\n%s\n' "${p0}" "${p1}" > "${PID_FILE}"
+
+    sleep 1
+    kill -0 "${p0}" 2>/dev/null || die "10G ping failed to start, see ${RAW_10G}"
+    kill -0 "${p1}" 2>/dev/null || die "1G ping failed to start, see ${RAW_1G}"
+    printf 'started (10G pid=%s, 1G pid=%s)\nlog: %s\n' "${p0}" "${p1}" "${LOG_FILE}"
 }
 
 do_stop() {
-    local pid i
-    pid="$(is_running)" || { printf 'not running\n'; rm -f "${PID_FILE}"; return 0; }
+    local pids p0 p1 i
 
-    kill -TERM -"${pid}" 2>/dev/null || kill -TERM "${pid}" 2>/dev/null
+    pids="$(is_running)" || {
+        printf 'not running\n'
+        rm -f "${PID_FILE}"
+        return 0
+    }
+    p0="${pids% *}"; p1="${pids#* }"
+
+    # SIGINT, not SIGTERM: ping prints its statistics block on interrupt, and
+    # that block is what the report parses.
+    kill -INT "${p0}" 2>/dev/null
+    kill -INT "${p1}" 2>/dev/null
     for (( i = 0; i < 20; i++ )); do
-        kill -0 "${pid}" 2>/dev/null || break
+        kill -0 "${p0}" 2>/dev/null || kill -0 "${p1}" 2>/dev/null || break
         sleep 0.5
     done
-    if kill -0 "${pid}" 2>/dev/null; then
-        printf 'SIGTERM ignored, sending SIGKILL\n'
-        kill -KILL -"${pid}" 2>/dev/null || kill -KILL "${pid}" 2>/dev/null
-    fi
+    kill -KILL "${p0}" 2>/dev/null
+    kill -KILL "${p1}" 2>/dev/null
+
+    write_report
     rm -f "${PID_FILE}"
-    printf 'stopped (pid=%s)\n' "${pid}"
+    printf 'stopped (10G pid=%s, 1G pid=%s)\nreport: %s\n' "${p0}" "${p1}" "${LOG_FILE}"
 }
 
 do_status() {
-    local pid
-    if pid="$(is_running)"; then
-        printf 'status : running (pid=%s)\n' "${pid}"
+    local pids
+    if pids="$(is_running)"; then
+        printf 'status : running (10G pid=%s, 1G pid=%s)\n' "${pids% *}" "${pids#* }"
     else
         printf 'status : stopped\n'
     fi
     printf 'log    : %s\n' "${LOG_FILE}"
-    [ -f "${LOG_FILE}" ] && printf 'size   : %s\n' "$(du -h "${LOG_FILE}" | cut -f1)"
-    printf 'ping   : count=%d, interval=%ds, settle=%ds\n' "${PING_COUNT}" "${INTERVAL_SEC}" "${LINK_SETTLE_SEC}"
-    printf '10G    : %s %s/%s -> %s (metric %s)\n' "${IF_10G}" "${IP_10G}" "${PLEN_10G}" "${TARGET_10G}" "${METRIC_10G}"
-    printf '1G     : %s %s/%s -> %s (metric %s)\n' "${IF_1G}" "${IP_1G}" "${PLEN_1G}" "${TARGET_1G}" "${METRIC_1G}"
+    printf '10G    : %s %s/%s -> %s\n' "${IF_10G}" "${IP_10G}" "${PLEN_10G}" "${TARGET_10G}"
+    printf '1G     : %s %s/%s -> %s\n' "${IF_1G}"  "${IP_1G}"  "${PLEN_1G}"  "${TARGET_1G}"
+    [ -f "${RAW_10G}" ] && printf '10G recv: %s\n' "$(grep -ac 'bytes from' "${RAW_10G}")"
+    [ -f "${RAW_1G}" ]  && printf '1G  recv: %s\n' "$(grep -ac 'bytes from' "${RAW_1G}")"
 }
 
 usage() {
     cat <<EOF
-Usage: ${SCRIPT_NAME} {start|stop|status|fg|tail|clear|summary}
+Usage: ${SCRIPT_NAME} {start|stop|status|summary|clear}
 
-  start    Run detached in the background; the previous log is discarded first
-           (see START_LOG_MODE)
-  stop     Stop the background instance
-  status   Show pid / log path / configured NICs
-  fg       Run in the foreground, output to the terminal (for a quick check)
-  tail     tail -f the log file  (does NOT return -- do not call from a macro)
-  clear    Remove the log file and all rotated copies (must be stopped first)
-  summary  Print just the per-leg RESULT lines from the log
+  start    Configure both NICs, warm up ARP, then ping from BOTH at the same
+           time and keep accumulating. The previous log is discarded first.
+  stop     Stop both pings and render the report into the log
+  status   Show pids, configured NICs and replies received so far
+  summary  Print just the RESULT lines from the log
+  clear    Remove the log and the raw captures (must be stopped first)
 
 Log file : ${LOG_FILE}
 
-One round = 10G leg then 1G leg, each pinging its own target. Both NICs are
-brought up and left up; addresses and routes are applied with
-"ip address/route replace", so repeating a round does not stack duplicates.
+The report holds, per NIC, the last ${TAIL_LINES} entries and the ping
+statistics, then "ip -s link show" for both interfaces.
 
-If both NICs share a subnet, keep ARP_STRICT=1 -- otherwise a reply can come
-back on the NIC that did not send it. Check nic_tx/nic_rx on the RESULT line:
-they are that interface's own counter delta across the burst.
-
-Edit the User Configurable Section at the top to change interfaces, addresses,
-targets, prefix lengths, gateways, metrics or the packet count.
+Both NICs are used at once, so management connectivity is in play -- drive
+this from the serial console. Edit the User Configurable Section at the top
+to change interfaces, addresses, targets or the ping options.
 EOF
 }
 
@@ -446,18 +389,15 @@ EOF
 # Entry point
 ###############################################################################
 case "${1:-}" in
-    start)    do_start ;;
-    stop)     do_stop ;;
-    status)   do_status ;;
-    fg)       LOG_TO_FILE=0; main_loop ;;
-    tail)     tail -n 50 -f "${LOG_FILE}" ;;
-    summary)  grep -a 'RESULT' "${LOG_FILE}" 2>/dev/null || printf 'no results in %s\n' "${LOG_FILE}" ;;
+    start)   do_start ;;
+    stop)    do_stop ;;
+    status)  do_status ;;
+    summary) grep -a 'RESULT' "${LOG_FILE}" 2>/dev/null || printf 'no results in %s\n' "${LOG_FILE}" ;;
     clear)
         is_running >/dev/null && die "still running, stop it first"
-        rm -f "${LOG_FILE}" "${LOG_FILE}".[0-9]*
+        rm -f "${LOG_FILE}" "${LOG_FILE}".[0-9]* "${RAW_10G}" "${RAW_1G}" "${STATE_FILE}"
         printf 'log cleared\n'
         ;;
-    __daemon) do_daemon ;;
     -h|--help|"") usage ;;
-    *)        printf '[ERROR] unknown sub-command: %s\n\n' "$1" >&2; usage; exit 1 ;;
+    *) printf '[ERROR] unknown sub-command: %s\n\n' "$1" >&2; usage; exit 1 ;;
 esac