please give me some advice about my script

koshihaku · 09-02-2010, 08:47 PM

The following code is for monitoring the memory used by apache processes. But I got a problem that the data I got by this script is much larger than the physical memory. It was said that there are some libraries used simultaneously by many processes, so the data I got has some double counted part. Because apache has many httpd processes.

Anyone have an idea of getting the multi-processes memory used? Thanks a lot!

Code:

#!/bin/sh
#G.sh 20100813

USAGE="Usage: $0 processName"

if [ "$#" -ne 1 ]; then
  echo "$USAGE"
  exit 1
fi

# In case the monitored process has not yet started
# keep searching until its PID is found
PROCESS_PID=""
while :
do
  PROCESS_PID=`/bin/pidof "$1"`

  if [ "$PROCESS_PID.X" != ".X" ]; then
    break
  fi
done

LOG_FILE="memusage.csv"

echo "ElapsedTime,VmSize,VmRSS" > "$LOG_FILE"

ELAPSED_TIME=`date +%H:%M:%S:%N`
PERIOD=2        # seconds

while :
do
  TOTAL_VM_SIZE=0
  TOTAL_VM_RSS=0

  for PID in $PROCESS_PID; do
    if [ -d "/proc/$PID" ] ; then
      VM_SIZE=`awk '/VmSize/ {print $2}' < "/proc/$PID/status"`
      if [ "$VM_SIZE.X" = ".X" ]; then
        continue
      fi
      VM_RSS=`awk '/VmRSS/ {print $2}' < "/proc/$PID/status"`
      if [ "$VM_RSS.X" = ".X" ]; then
        continue
      fi
      let TOTAL_VM_SIZE+=VM_SIZE
      let TOTAL_VM_RSS+=VM_RSS
    else
      echo "$1 ($PID) is no longer a running process"
      exit 0
    fi
  done

  echo "$ELAPSED_TIME,$TOTAL_VM_SIZE,$TOTAL_VM_RSS" >> "$LOG_FILE"
  sleep "$PERIOD"
  ELAPSED_TIME=`date +%H:%M:%S:%N`
done

kbp · 09-02-2010, 11:57 PM

Maybe subtracting VmLib from each process will be more accurate...

cheers

koshihaku · 09-03-2010, 12:12 AM

Quote:

Originally Posted by kbp

Maybe subtracting VmLib from each process will be more accurate...

cheers

but the VmLib is often larger than the VmRss e.g.
VmPeak: 67980 kB
VmSize: 67976 kB
VmLck: 0 kB
VmHWM: 5676 kB
VmRSS: 5672 kB
VmData: 4504 kB
VmStk: 84 kB
VmExe: 372 kB
VmLib: 15324 kB

And after I revising my script as the following

Code:

#!/bin/bash
#G.sh 20100813

USAGE="Usage: $0 processName"

if [ "$#" -ne 1 ]; then
  echo "$USAGE"
  exit 1
fi

# In case the monitored process has not yet started
# keep searching until its PID is found
PROCESS_PID=""
while :
do
  PROCESS_PID=`/bin/pidof "$1"`

  if [ "$PROCESS_PID.X" != ".X" ]; then
    break
  fi
done

LOG_FILE="memusage.csv"

echo "ElapsedTime,VmSize,VmRSS" > "$LOG_FILE"

ELAPSED_TIME=`date +%H:%M:%S:%N`
PERIOD=0.5      # seconds

while :
do
  TOTAL_VM_SIZE=0
  TOTAL_VM_RSS=0
  VmLib=0

  for PID in $PROCESS_PID; do
    if [ -d "/proc/$PID" ] ; then
      VM_SIZE=`awk '/VmSize/ {print $2}' < "/proc/$PID/status"`
      if [ "$VM_SIZE.X" = ".X" ]; then
        continue
      fi
      VM_RSS=`awk '/VmRSS/ {print $2}' < "/proc/$PID/status"`
      if [ "$VM_RSS.X" = ".X" ]; then
        continue
      fi
      VmLib=`awk '/VmLib/ {print $2}' < "/proc/$PID/status"`
      if [ "$VmLib.X" = ".X" ]; then
        continue
      fi
      let REAL_VM_SIZE=VM_SIZE-VmLib
      let TOTAL_VM_SIZE+=REAL_VM_SIZE
      let TOTAL_VM_RSS+=VM_RSS
    fi
  done

  echo "$ELAPSED_TIME,$TOTAL_VM_SIZE,$TOTAL_VM_RSS,$MemFree" >> "$LOG_FILE"
  sleep "$PERIOD"
  ELAPSED_TIME=`date +%H:%M:%S:%N`
done

I got the result : ElapsedTime VmSize VmRSS
14:08:14:487053684 31643556 3456272
14:08:28:750838950 31643556 3456272

but the physical memory is only 1G...

kbp · 09-03-2010, 02:03 AM

It seems what you really want is the sum of private RSS ... someone has already written a script to do what you are trying to do though if that helps .. http://www.pixelbeat.org/scripts/ps_mem.py

cheers

koshihaku · 09-03-2010, 09:34 PM

Quote:

Originally Posted by kbp

It seems what you really want is the sum of private RSS ... someone has already written a script to do what you are trying to do though if that helps .. http://www.pixelbeat.org/scripts/ps_mem.py

cheers

Thank you very much! I think it will help alot. I will try it now.

koshihaku · 09-03-2010, 10:04 PM

Quote:

Originally Posted by kbp

It seems what you really want is the sum of private RSS ... someone has already written a script to do what you are trying to do though if that helps .. http://www.pixelbeat.org/scripts/ps_mem.py

cheers

It is good! But I need to record the output every several seconds in a log file. I don't know python. Is there a way to run it periodically can write the realtime output to file?

kbp · 09-03-2010, 10:21 PM

If you don't know python maybe you could wrap it in a shell script :

Code:

...
while :
do
  ./ps_mem.py httpd >> process.log
  sleep "$PERIOD"
done
...

koshihaku · 09-03-2010, 11:21 PM

Quote:

Originally Posted by kbp

If you don't know python maybe you could wrap it in a shell script :

Code:

...
while :
do
  ./ps_mem.py httpd >> process.log
  sleep "$PERIOD"
done
...

Thanks, I wraped the script into my shell script, I am trying it.

I think it will work, thanks a lot

koshihaku · 09-03-2010, 11:29 PM

Quote:

Originally Posted by kbp

If you don't know python maybe you could wrap it in a shell script :

Code:

...
while :
do
  ./ps_mem.py httpd >> process.log
  sleep "$PERIOD"
done
...

Oh, I > the output to output.csv

what is the difference between the .csv and .log ? It worked when I use .csv

kbp · 09-05-2010, 10:18 AM

Your script was writing output as csv, you may have to massage the data from this one if you want in it the same format

koshihaku · 09-09-2010, 02:00 AM

Quote:

Originally Posted by kbp

Your script was writing output as csv, you may have to massage the data from this one if you want in it the same format

I run the script when benchmarking the server by httperf, but there is no changing of memory used in the output. Do you have any idea about this?

kbp · 09-09-2010, 09:22 AM

Maybe it's handling the load with the currently allocated resources .. ?

koshihaku · 09-09-2010, 11:28 PM

Quote:

Originally Posted by kbp

Maybe it's handling the load with the currently allocated resources .. ?

Is there a way to run this script in a high priority? Because when the server is saturated, there is no output until the workload is low. I want the script run inspite of high workload.

kbp · 09-10-2010, 01:23 AM

'man nice'

koshihaku · 09-10-2010, 01:26 AM

Quote:

Originally Posted by kbp

'man nice'

I input:
# sudo bash processname &

and returned the pid of processname ,then

sudo nice -20 pid

Is there a way to get the pid of processname or bash without running with &?
I mean run the script and return the pid of it .