Added SIGINT and SIGTERM signal handling to sweep script.

sweep.bash

@@ -13,9 +13,10 @@
 # Author: Mikael Henriksson
 #
 
+
 #
-# Global sweeping settings.
-# -------------------------
+# Global sweeping settings begin:
+# -------------------------------
 #
 
 # Top level design entity name.
@@ -23,18 +24,18 @@ DESIGN_NAME="my_divider"
 
 # BASH-style array with design files to be analyzed by Design Compiler. Analisys
 # of files are done from left (first element) to right (last element).
-DESIGN_FILES=("divider.vhdl")
+DESIGN_FILES=("div.vhdl")
 
 # BASH-style array with periods (in the technology time unit) to be sweept.
-PERIODS=(10.00 5.00 2.50 1.25)
+PERIODS=(10.0 5.0 3.333 2.5 2.0 1.666 1.428 1.25 1.111 1.0)
 
 # BASH-style array with generics to be sweept. Leave empty if no design generic
 # should be set. Multiple generics can be assigned for one sweep by comma
 # separating each generic assignment in the BASH-array element.
-GENERICS=("pipeline=0" "pipeline=1" "pipeline=2")
-#GENERICS=()
+GENERICS=( "float_ip=0,pipe_stages=1" "float_ip=0,pipe_stages=2"
+           "float_ip=1,pipe_stages=1" "float_ip=1,pipe_stages=2" )
 
-# Design clock name to be sweept. The design must have a clock signal.
+# Design clock name to be sweept. The design MUST have a clock signal.
 CLOCK_NAME="clk"
 
 # Enable Design Compiler adaptive retime through 'set_optimize_registers' for
@@ -96,10 +97,7 @@ function sweep_to_csv() {
 }
 
 # Join elements of BASH array, or white space separated string, in $2 by the
-# string in $1. Example usage:
-#| > MY_ARRAY=('a' 'b' 'c')
-#| > echo join_by '---' "${MY_ARRAY[@]}"
-#| a---b---c
+# string in $1.
 function join_by {
     local d=$1; shift; local f=$1; shift; printf %s "$f" "${@/#/$d}";
 }
@@ -128,6 +126,7 @@ function generate_synthesis_script() {
 # and invoke this function. Note to programmer, that means this function cannot
 # access any unexported items (variables, functions, etc).
 function run_design_compiler() {
+
     # Change directory to design directory.
     local design_directory="$1"
     cd "$design_directory" || exit 1
@@ -166,15 +165,23 @@ function run_design_compiler() {
     fi
 }
 
-# Export functions and variables needed by the forked instances of this script
-# that run the run_design_compiler function.
+# Signal SIGINT and SIGTERM interrupt handlers. Both are registered once the
+# setup is complete and the actual sweep has started.
+function sigint_handler() {
+    echo "${0}: SIGINT ignored. Send SIGTERM to terminate sweep."
+}
+function sigterm_handler() {
+    echo "${0}: SIGTERM recieved, propagating to workers and terminating."
+    kill -s SIGTERM -"${1}"
+    exit 1
+}
+
+# Export functions and variables needed by the forked workers.
 export -f run_design_compiler
 export DESIGN_NAME
 export PERIOD_DIM
 
-#
 # Sanity checks for the global settings.
-#
 if [ -z "$CLOCK_NAME" ]; then
     echo "Error: No clock name (\$CLOCK_NAME) provided."
     exit 1
@@ -236,9 +243,21 @@ want to continure? [y/N] " response
     fi
 fi
 
+# Get absolute path of design files, which is necessary for the sweep.
+DESIGN_FILES_ABS=()
+for file in "${DESIGN_FILES[@]}"; do
+    DESIGN_FILES_ABS+=("$(realpath "$file")")
+done
+
 # Get script launch date.
 SCRIPT_LAUNCH_DATE=$(date +"%F_%H:%M:%S")
 
+
+#
+# Setup of sweep complete. Generate the sweep top directory, launch all sweep
+# workers according to the max concurreny and register signal handlers.
+#
+
 # Create sweep top directory.
 if [ -z "$TOP_DIR_APPEND" ]; then
     TOP_DIR="sweep_${DESIGN_NAME}_${SCRIPT_LAUNCH_DATE}"
@@ -252,12 +271,6 @@ fi
 echo "Created top directory: '$TOP_DIR'"
 echo ""
 
-# Get absolute path of design files, which is necessary for the sweep.
-DESIGN_FILES_ABS=()
-for file in "${DESIGN_FILES[@]}"; do
-    DESIGN_FILES_ABS+=("$(realpath "$file")")
-done
-
 # Initialize designs. We create one sub directory for each design that is
 # to be sweept. A 'design' is exactly one setting from ${DESIGN_GENERICS[@]}.
 # Further, we substitue design options into 'template.tcl' and copy the
@@ -335,14 +348,35 @@ else # "${GENERICS[@]}" is empty.
     done
 fi
 
-# Print start of process pool log.
-printf "\nParallel synthesis log ($MAX_CONCURRENCY concurrent processes):\n"
-
-# Launch workers according to the max concurrency with xargs.
-printf '%s' "${SYNTH_DIRS%?}" | xargs -L1 -d "|" --max-procs="$MAX_CONCURRENCY"\
-    bash -c 'run_design_compiler $@' _
+# Display start of process pool log message.
+printf "\nParallel synthesis log (max $MAX_CONCURRENCY concurrent processes):\n"
+
+# Trap incoming SIGINT signals, which might be accidental and can prematurely
+# terminate the sweep. User should use SIGTERM to terminate sweep beyond this
+# point.
+#trap 'echo "$0: SIGINT ignored. Send SIGTERM to terminate sweep."' SIGINT
+trap 'sigint_handler' SIGINT
+
+# Launch workers according to the max concurrency with XARGS. By launching XARGS
+# through SETSID, all workers are launched in the same process group, and more
+# importantly, in a new process group different from that of this parent sweep
+# script. This shileds all worker processes from recieving SIGINT on accidental
+# shell <Ctrl+C>. The process group id (PGID) of all workers is equal to the
+# process id (PID) of XARGS, and can be used if a signal must be sent to all
+# workers.
+printf '%s' "${SYNTH_DIRS%?}" | setsid xargs -L1 -d "|" --max-procs="$MAX_CONCURRENCY"\
+    bash -c 'run_design_compiler $@' _ &
+XARGS_PID="$!"
+
+# Register SIGTERM handler.
+trap "sigterm_handler ${XARGS_PID}" SIGTERM
+
+# Wait for all sweep workers to finish.
+while kill -s 0 ${XARGS_PID} 1>/dev/null 2>&1; do
+    wait ${XARGS_PID}
+done
 
-# Print end of process pool log.
+# Display end of process pool log message.
 echo "End of parallel synthesis log."