…net#25643)

* [build] Add build timing report and dependency analysis tools

Add three scripts for build performance instrumentation:

- scripts/build-timing-report.sh: Parse per-package timing from build
  logs (HEADER/FOOTER timestamps), generate sorted duration table,
  phase breakdown, parallelism timeline, and CSV export.

- scripts/build-dep-graph.py: Parse rules/*.mk dependency graph,
  compute critical path, fan-out/fan-in bottleneck analysis, and
  generate DOT/JSON output for visualization.

- scripts/build-resource-monitor.sh: Sample CPU, memory, disk I/O,
  and Docker container count during builds for resource utilization
  analysis.

Add "make build-report" target to slave.mk that runs the timing
report and dependency analysis after a build completes.

Example output from a VS build on 24-core/30GB machine:
- 210 packages built in 53m wall time (173m CPU)
- Max concurrency: 5 (with SONIC_CONFIG_BUILD_JOBS=4)
- Critical path: 14 packages deep (libnl -> libswsscommon -> utilities)
- Top bottleneck: LIBSWSSCOMMON with 48 downstream dependents

Signed-off-by: Rustiqly <rustiqly@users.noreply.github.com>

* Address Copilot review: fix 17 bugs in build analysis scripts

- Use free -m with division instead of free -g to avoid rounding (#1)
- Add = and ?= to Makefile dependency regex patterns (#2, #7)
- CPU calculation now uses /proc/stat delta (two reads) (#3, sonic-net#14)
- Fix misleading 'critical path estimate' comment (#4)
- Fix parallelism timeline comment (60s not 10s) (#5)
- Include after-relationship packages in fan stats (#6)
- Guard disk I/O division by zero when INTERVAL<=1 (#8)
- Remove unused elapsed_line variable (#9)
- Remove redundant LIBSWSSCOMMON_DBG check (#10)
- Remove active_make_jobs from CSV header comment (#11)
- Wire up _RDEPENDS parsing to build reverse deps (#12)
- Remove unnecessary 'if v' filter on rdeps JSON (#13)
- Remove unused REPORT_FORMAT parameter (sonic-net#15)
- Add cycle detection to critical path algorithm (sonic-net#16)
- Add execute permission check for companion scripts (sonic-net#17)

Signed-off-by: Rustiqly <rustiqly@users.noreply.github.com>

---------

Signed-off-by: Rustiqly <rustiqly@users.noreply.github.com>
Co-authored-by: Rustiqly <rustiqly@users.noreply.github.com>

…dating udevd rules (sonic-net#26343)

- Why I did it
On SONiC SmartSwitch platforms with DPUs, systemd-udevd crashes with SIGABRT on every reboot when DPU firmware initialization is slow. During the initramfs boot phase, a standalone systemd-udevd daemon is started to handle device discovery. If DPU firmware takes longer than the 60-second udevadm settle timeout (BlueField-3 DPUs can take 120 seconds each in the failure case when they are stuck), the initramfs cannot stop this udevd before switch_root. The stale process survives into the real system but is never chrooted into the overlayfs root, leaving it with a broken filesystem view. When dpu-udev-manager.sh writes udev rules, the stale udevd detects the change and crashes on an assertion in systemd's chase() path resolution (assert(path_is_absolute(p)) at chase.c:648), because dir_fd_is_root() returns false for a process whose root still points to the initramfs rootfs rather than the overlayfs.

This triggers a systemd issue : systemd/systemd#29559 which maintainers doesn't consider as a bug from systemd side. Raising this fix for our usecase.

Core was generated by `/usr/lib/systemd/systemd-udevd --daemon --resolve-names=never'.
Program terminated with signal SIGABRT, Aborted.
#0  0x00007f29fe7f695c in ?? () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt
#0  0x00007f29fe7f695c in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007f29fe7a1cc2 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#2  0x00007f29fe78a4ac in abort () from /lib/x86_64-linux-gnu/libc.so.6
#3  0x00007f29fea50c11 in ?? () from /usr/lib/x86_64-linux-gnu/systemd/libsystemd-shared-257.so
#4  0x00007f29feb94a8b in chase () from /usr/lib/x86_64-linux-gnu/systemd/libsystemd-shared-257.so
#5  0x00007f29feb956e2 in chase_and_opendir () from /usr/lib/x86_64-linux-gnu/systemd/libsystemd-shared-257.so
#6  0x00007f29feb9a609 in conf_files_list_strv () from /usr/lib/x86_64-linux-gnu/systemd/libsystemd-shared-257.so
#7  0x00007f29fea913e8 in config_get_stats_by_path () from /usr/lib/x86_64-linux-gnu/systemd/libsystemd-shared-257.so
#8  0x0000559f295519cf in ?? ()
#9  0x0000559f29553a77 in ?? ()
#10 0x00007f29fec36055 in ?? () from /usr/lib/x86_64-linux-gnu/systemd/libsystemd-shared-257.so
#11 0x00007f29fec3668d in sd_event_dispatch () from /usr/lib/x86_64-linux-gnu/systemd/libsystemd-shared-257.so
#12 0x00007f29fec394a8 in sd_event_run () from /usr/lib/x86_64-linux-gnu/systemd/libsystemd-shared-257.so
#13 0x00007f29fec396c7 in sd_event_loop () from /usr/lib/x86_64-linux-gnu/systemd/libsystemd-shared-257.so
sonic-net#14 0x0000559f29545820 in ?? ()
sonic-net#15 0x00007f29fe78bca8 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
sonic-net#16 0x00007f29fe78bd65 in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
sonic-net#17 0x0000559f29545c51 in ?? ()

- How I did it
Added a kill_stale_udevd() function to dpu-udev-manager.sh that runs before writing the udev rules. It identifies the systemd-managed udevd PID via systemctl show, then kills any other systemd-udevd --daemon process that doesn't match -- these are leftover initramfs instances. If no stale process exists (e.g. DPUs are healthy and the initramfs udevd exited cleanly), the function is a no-op.

- How to verify it
Deploy the image on a SmartSwitch with DPUs in a state where firmware initialization times out (>60s per DPU) by stopping image installation before firmware install step
Reboot the switch
Verify no new systemd-udevd coredumps in /var/core/
Verify the stale process was killed: journalctl -b 0 | grep dpu-udev-manager should show killing stale initramfs udevd PID (systemd udevd is PID )
Verify systemd-udevd.service is healthy: systemctl status systemd-udevd should show active (running)
Verify DPU udev rules were written: cat /etc/udev/rules.d/92-midplane-intf.rules should contain the DPU interface naming rules

Signed-off-by: Hemanth Kumar Tirupati <tirupatihemanthkumar@gmail.com>