[S] Parallelize patch_binary usage

Spawn $n_jobs count processes to do patch_binary in parallel. A pipe is used to
dispatch the files among the processes.

With previous patches for warnings elimination and parallelization time for
patching binaries goes from ~230sec -> 6sec (with sanitized environment)

Change-Id: Iae3859d67f700b90fae809c45bea706b3e6162e4

4 files changed, 152 insertions, 16 deletions

diff --git a/packaging/qemu-accel-aarch64.spec b/packaging/qemu-accel-aarch64.spec
index 621343d..c011fdf 100644
--- a/packaging/qemu-accel-aarch64.spec
+++ b/packaging/qemu-accel-aarch64.spec
@@ -244,10 +244,44 @@ function patch_binary {
   fi
 }
 
-for binary in $binaries
-do
-  patch_binary $binary $LD
-done
+# Spawn single job which reads input to extract filename by index
+function run_single_job() {
+    local arg="$1"
+    while :; do
+	# Reads (FILENUM_DIGITS + 1) bytes. Note: to drop redirection usage we
+	# need dd with support for status=none
+	filenum=$(dd bs=$(( FILENUM_DIGITS + 1 )) count=1 2>/dev/null)
+	if [[ -z "$filenum" ]]; then
+	    break
+	fi
+	# Get filename for 0x$filenum index and process it
+	patch_binary "${bin_array[$((0x$filenum))]}" "$LD"
+    done
+}
+
+# Converting to the bash array to allow access by index
+bin_array=($binaries)
+# Use processors count + arbitrary addend.
+n_jobs=$(( $(/usr/bin/getconf _NPROCESSORS_ONLN) + 3 ))
+# Supports up to 16^FILENUM_DIGITS - 1 files:
+# 16^5 - 1 = 1.048.575 files
+FILENUM_DIGITS=5
+
+# Send the input for the jobs: enumerate all files
+for ((file = 0; file < ${#bin_array[@]}; file++)); do
+    printf "%0${FILENUM_DIGITS}x\\n" $file
+done | (
+    # Implementing simple Round-robin scheduling routine
+    exec 3<&0
+    echo "Spawn $n_jobs jobs"
+    for ((i = 0; i < n_jobs; i++)); do
+	# The shell redirects stdin to /dev/null for background jobs. Work
+	# around this by duplicating fd 0
+	run_single_job $i <&3 &
+    done
+    wait
+)
+
 set -x
 
 %{?multilib:
diff --git a/packaging/qemu-accel-armv7hl.spec b/packaging/qemu-accel-armv7hl.spec
index 0af6571..6d8cdb5 100644
--- a/packaging/qemu-accel-armv7hl.spec
+++ b/packaging/qemu-accel-armv7hl.spec
@@ -244,10 +244,44 @@ function patch_binary {
   fi
 }
 
-for binary in $binaries
-do
-  patch_binary $binary $LD
-done
+# Spawn single job which reads input to extract filename by index
+function run_single_job() {
+    local arg="$1"
+    while :; do
+	# Reads (FILENUM_DIGITS + 1) bytes. Note: to drop redirection usage we
+	# need dd with support for status=none
+	filenum=$(dd bs=$(( FILENUM_DIGITS + 1 )) count=1 2>/dev/null)
+	if [[ -z "$filenum" ]]; then
+	    break
+	fi
+	# Get filename for 0x$filenum index and process it
+	patch_binary "${bin_array[$((0x$filenum))]}" "$LD"
+    done
+}
+
+# Converting to the bash array to allow access by index
+bin_array=($binaries)
+# Use processors count + arbitrary addend.
+n_jobs=$(( $(/usr/bin/getconf _NPROCESSORS_ONLN) + 3 ))
+# Supports up to 16^FILENUM_DIGITS - 1 files:
+# 16^5 - 1 = 1.048.575 files
+FILENUM_DIGITS=5
+
+# Send the input for the jobs: enumerate all files
+for ((file = 0; file < ${#bin_array[@]}; file++)); do
+    printf "%0${FILENUM_DIGITS}x\\n" $file
+done | (
+    # Implementing simple Round-robin scheduling routine
+    exec 3<&0
+    echo "Spawn $n_jobs jobs"
+    for ((i = 0; i < n_jobs; i++)); do
+	# The shell redirects stdin to /dev/null for background jobs. Work
+	# around this by duplicating fd 0
+	run_single_job $i <&3 &
+    done
+    wait
+)
+
 set -x
 
 %{?multilib:
diff --git a/packaging/qemu-accel-armv7l.spec b/packaging/qemu-accel-armv7l.spec
index 70012d1..86130b2 100644
--- a/packaging/qemu-accel-armv7l.spec
+++ b/packaging/qemu-accel-armv7l.spec
@@ -244,10 +244,44 @@ function patch_binary {
   fi
 }
 
-for binary in $binaries
-do
-  patch_binary $binary $LD
-done
+# Spawn single job which reads input to extract filename by index
+function run_single_job() {
+    local arg="$1"
+    while :; do
+	# Reads (FILENUM_DIGITS + 1) bytes. Note: to drop redirection usage we
+	# need dd with support for status=none
+	filenum=$(dd bs=$(( FILENUM_DIGITS + 1 )) count=1 2>/dev/null)
+	if [[ -z "$filenum" ]]; then
+	    break
+	fi
+	# Get filename for 0x$filenum index and process it
+	patch_binary "${bin_array[$((0x$filenum))]}" "$LD"
+    done
+}
+
+# Converting to the bash array to allow access by index
+bin_array=($binaries)
+# Use processors count + arbitrary addend.
+n_jobs=$(( $(/usr/bin/getconf _NPROCESSORS_ONLN) + 3 ))
+# Supports up to 16^FILENUM_DIGITS - 1 files:
+# 16^5 - 1 = 1.048.575 files
+FILENUM_DIGITS=5
+
+# Send the input for the jobs: enumerate all files
+for ((file = 0; file < ${#bin_array[@]}; file++)); do
+    printf "%0${FILENUM_DIGITS}x\\n" $file
+done | (
+    # Implementing simple Round-robin scheduling routine
+    exec 3<&0
+    echo "Spawn $n_jobs jobs"
+    for ((i = 0; i < n_jobs; i++)); do
+	# The shell redirects stdin to /dev/null for background jobs. Work
+	# around this by duplicating fd 0
+	run_single_job $i <&3 &
+    done
+    wait
+)
+
 set -x
 
 %{?multilib:
diff --git a/packaging/qemu-accel.spec.in b/packaging/qemu-accel.spec.in
index e5fc9b8..192c077 100644
--- a/packaging/qemu-accel.spec.in
+++ b/packaging/qemu-accel.spec.in
@@ -241,10 +241,44 @@ function patch_binary {
   fi
 }
 
-for binary in $binaries
-do
-  patch_binary $binary $LD
-done
+# Spawn single job which reads input to extract filename by index
+function run_single_job() {
+    local arg="$1"
+    while :; do
+	# Reads (FILENUM_DIGITS + 1) bytes. Note: to drop redirection usage we
+	# need dd with support for status=none
+	filenum=$(dd bs=$(( FILENUM_DIGITS + 1 )) count=1 2>/dev/null)
+	if [[ -z "$filenum" ]]; then
+	    break
+	fi
+	# Get filename for 0x$filenum index and process it
+	patch_binary "${bin_array[$((0x$filenum))]}" "$LD"
+    done
+}
+
+# Converting to the bash array to allow access by index
+bin_array=($binaries)
+# Use processors count + arbitrary addend.
+n_jobs=$(( $(/usr/bin/getconf _NPROCESSORS_ONLN) + 3 ))
+# Supports up to 16^FILENUM_DIGITS - 1 files:
+# 16^5 - 1 = 1.048.575 files
+FILENUM_DIGITS=5
+
+# Send the input for the jobs: enumerate all files
+for ((file = 0; file < ${#bin_array[@]}; file++)); do
+    printf "%0${FILENUM_DIGITS}x\\n" $file
+done | (
+    # Implementing simple Round-robin scheduling routine
+    exec 3<&0
+    echo "Spawn $n_jobs jobs"
+    for ((i = 0; i < n_jobs; i++)); do
+	# The shell redirects stdin to /dev/null for background jobs. Work
+	# around this by duplicating fd 0
+	run_single_job $i <&3 &
+    done
+    wait
+)
+
 set -x
 
 %{?multilib: