[1/1] rt-tests: determine_maximum_mpps.sh: Introduce '-F' option to specify CPU frequency

[1/1] rt-tests: determine_maximum_mpps.sh: Introduce '-F' option to specify CPU frequency

[ende.tan]

From: Tan En De <ende.tan@starfivetech.com>

For platform that doesn't show cpu MHz in /proc/cpuinfo, introduce '-F'
option for user to specify the CPU frequency in MHz.

This corrects previous commit that mistakenly used timer frequency
(timebase-frequency) instead of CPU frequency.

Fixes: fab7d9057887 ("rt-tests: determine_maximum_mpps.sh: Get frequency from timebase-frequency if cpuinfo fails")
Signed-off-by: Tan En De <ende.tan@starfivetech.com>
---
 src/queuelat/determine_maximum_mpps.8  |  3 +++
 src/queuelat/determine_maximum_mpps.sh | 17 +++++++++--------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/queuelat/determine_maximum_mpps.8 b/src/queuelat/determine_maximum_mpps.8
index ba2cc2a..bcd3078 100644
--- a/src/queuelat/determine_maximum_mpps.8
+++ b/src/queuelat/determine_maximum_mpps.8
@@ -56,6 +56,9 @@ default priority = 1. Valid numbers are from 1 to 99
 .TP
 .B \-h
 help
+.TP
+.B \-F cpu_mhz
+CPU frequency in MHz. This is required for platform that does not show cpu MHz in /proc/cpuinfo.
 .LP
 .SH AUTHOR
 determine_maximum_mpps was written by
diff --git a/src/queuelat/determine_maximum_mpps.sh b/src/queuelat/determine_maximum_mpps.sh
index adfd809..6a90ca0 100755
--- a/src/queuelat/determine_maximum_mpps.sh
+++ b/src/queuelat/determine_maximum_mpps.sh
@@ -37,20 +37,20 @@ usage()
 	echo "-h"
 	echo "	help"
 	echo "	print this help message and exit"
+	echo "-F cpu_mhz"
+	echo "	CPU frequency in MHz. This is required for platform that does not show cpu MHz in /proc/cpuinfo"
 	exit
 }
 
 get_cpuinfo_mhz()
 {
-	# Try to determine MHz from /proc/cpuinfo
-	FREQ_MHZ=$(grep "cpu MHz" /proc/cpuinfo | cut -f 3 -d " " | sort -rn | head -n1)
-
-	# Try to determine MHz from /sys/firmware/devicetree/base/cpus/timebase-frequency
-	if [ -z $FREQ_MHZ ]; then
-		FREQ_MHZ=$(($((16#$(hexdump -e '1/1 "%02X"' /sys/firmware/devicetree/base/cpus/timebase-frequency)))/1000000))
+	# If user does not specify -F CPU_MHZ
+	if [ -z $CPU_MHZ ]; then
+		# Try to determine MHz from /proc/cpuinfo
+		CPU_MHZ=$(grep "cpu MHz" /proc/cpuinfo | cut -f 3 -d " " | sort -rn | head -n1)
 	fi
 
-	echo "$FREQ_MHZ"
+	echo "$CPU_MHZ"
 }
 
 # Check that the scheduling policy hasn't already been set
@@ -64,7 +64,7 @@ check_sched()
 }
 
 # Process command line options
-while getopts ":a:frp:m:n:h" opt; do
+while getopts ":a:frp:m:n:hF:" opt; do
 	case ${opt} in
 		a ) CPULIST="${OPTARG}" ;;
 		m ) MAXLAT="${OPTARG}" ;;
@@ -73,6 +73,7 @@ while getopts ":a:frp:m:n:h" opt; do
 		r ) check_sched; SCHED="-r" ;;
 		p ) PRIO="${OPTARG}" ;;
 		h ) usage ;;
+		F ) CPU_MHZ="${OPTARG}" ;;
 		* ) echo "no such option"; usage ;;
 	esac
 done
-- 
2.34.1

Re: [1/1] rt-tests: determine_maximum_mpps.sh: Introduce '-F' option to specify CPU frequency

[John Kacur]

On Thu, 12 Dec 2024, ende.tan@starfivetech.com wrote:

> From: Tan En De <ende.tan@starfivetech.com>
> 
> For platform that doesn't show cpu MHz in /proc/cpuinfo, introduce '-F'
> option for user to specify the CPU frequency in MHz.
>

Are there other places to get this information, for example
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq

 
> This corrects previous commit that mistakenly used timer frequency
> (timebase-frequency) instead of CPU frequency.
> 
> Fixes: fab7d9057887 ("rt-tests: determine_maximum_mpps.sh: Get frequency from timebase-frequency if cpuinfo fails")
> Signed-off-by: Tan En De <ende.tan@starfivetech.com>
> ---
>  src/queuelat/determine_maximum_mpps.8  |  3 +++
>  src/queuelat/determine_maximum_mpps.sh | 17 +++++++++--------
>  2 files changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/src/queuelat/determine_maximum_mpps.8 b/src/queuelat/determine_maximum_mpps.8
> index ba2cc2a..bcd3078 100644
> --- a/src/queuelat/determine_maximum_mpps.8
> +++ b/src/queuelat/determine_maximum_mpps.8
> @@ -56,6 +56,9 @@ default priority = 1. Valid numbers are from 1 to 99
>  .TP
>  .B \-h
>  help
> +.TP
> +.B \-F cpu_mhz
> +CPU frequency in MHz. This is required for platform that does not show cpu MHz in /proc/cpuinfo.
>  .LP
>  .SH AUTHOR
>  determine_maximum_mpps was written by
> diff --git a/src/queuelat/determine_maximum_mpps.sh b/src/queuelat/determine_maximum_mpps.sh
> index adfd809..6a90ca0 100755
> --- a/src/queuelat/determine_maximum_mpps.sh
> +++ b/src/queuelat/determine_maximum_mpps.sh
> @@ -37,20 +37,20 @@ usage()
>  	echo "-h"
>  	echo "	help"
>  	echo "	print this help message and exit"
> +	echo "-F cpu_mhz"
> +	echo "	CPU frequency in MHz. This is required for platform that does not show cpu MHz in /proc/cpuinfo"
>  	exit
>  }
>  
>  get_cpuinfo_mhz()
>  {
> -	# Try to determine MHz from /proc/cpuinfo
> -	FREQ_MHZ=$(grep "cpu MHz" /proc/cpuinfo | cut -f 3 -d " " | sort -rn | head -n1)
> -
> -	# Try to determine MHz from /sys/firmware/devicetree/base/cpus/timebase-frequency
> -	if [ -z $FREQ_MHZ ]; then
> -		FREQ_MHZ=$(($((16#$(hexdump -e '1/1 "%02X"' /sys/firmware/devicetree/base/cpus/timebase-frequency)))/1000000))
> +	# If user does not specify -F CPU_MHZ
> +	if [ -z $CPU_MHZ ]; then
> +		# Try to determine MHz from /proc/cpuinfo
> +		CPU_MHZ=$(grep "cpu MHz" /proc/cpuinfo | cut -f 3 -d " " | sort -rn | head -n1)
>  	fi
>  
> -	echo "$FREQ_MHZ"
> +	echo "$CPU_MHZ"
>  }
>  
>  # Check that the scheduling policy hasn't already been set
> @@ -64,7 +64,7 @@ check_sched()
>  }
>  
>  # Process command line options
> -while getopts ":a:frp:m:n:h" opt; do
> +while getopts ":a:frp:m:n:hF:" opt; do
>  	case ${opt} in
>  		a ) CPULIST="${OPTARG}" ;;
>  		m ) MAXLAT="${OPTARG}" ;;
> @@ -73,6 +73,7 @@ while getopts ":a:frp:m:n:h" opt; do
>  		r ) check_sched; SCHED="-r" ;;
>  		p ) PRIO="${OPTARG}" ;;
>  		h ) usage ;;
> +		F ) CPU_MHZ="${OPTARG}" ;;
>  		* ) echo "no such option"; usage ;;
>  	esac
>  done
> -- 
> 2.34.1
> 
> 
> 

RE: [1/1] rt-tests: determine_maximum_mpps.sh: Introduce '-F' option to specify CPU frequency

[EnDe Tan]

> Are there other places to get this information, for example
> /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq
It is possible to specify "clock-frequency" in CPU nodes in device tree,
which corresponds to entry like this
/sys/devices/system/cpu/cpu0/of_node/clock-frequency

However, it's not mandatory to specify "clock-frequency", so maybe
adding a '-F' option is more useful.

RE: [1/1] rt-tests: determine_maximum_mpps.sh: Introduce '-F' option to specify CPU frequency

[John Kacur]

On Thu, 12 Dec 2024, EnDe Tan wrote:

> > Are there other places to get this information, for example
> > /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq
> It is possible to specify "clock-frequency" in CPU nodes in device tree,
> which corresponds to entry like this
> /sys/devices/system/cpu/cpu0/of_node/clock-frequency
> 
> However, it's not mandatory to specify "clock-frequency", so maybe
> adding a '-F' option is more useful.
> 
> 
But why we would want to allow the user to specify a potentially arbitrary 
number, when we can get a more accurate one from the OS?

Do you have any comments Marcelo?

John