Thursday, October 15, 2009

Linux Memory use

#!/usr/bin/python
import os, sys, time
a="\x00"*(32*1024*1024) #alloc 32MiB
pid=os.fork()
if(not pid):
time.sleep(1)
sys.exit()
sizel=map(float,open("/proc/"+str(pid)+"/statm").readlines()[0].split()[1:3])
print "only %.1f%% reported as shared" % ((sizel[1]/sizel[0])*100)
os.wait()


--

import sys, os, string

if os.geteuid() != 0:
sys.stderr.write("Sorry, root permission required.\n");
sys.exit(1)

PAGESIZE=os.sysconf("SC_PAGE_SIZE")/1024 #KiB
our_pid=os.getpid()

#(major,minor,release)
def kernel_ver():
kv=open("/proc/sys/kernel/osrelease").readline().split(".")[:3]
for char in "-_":
kv[2]=kv[2].split(char)[0]
return (int(kv[0]), int(kv[1]), int(kv[2]))

kv=kernel_ver()

have_pss=0

#return Private,Shared
#Note shared is always a subset of rss (trs is not always)
def getMemStats(pid):
global have_pss
Private_lines=[]
Shared_lines=[]
Pss_lines=[]
Rss=int(open("/proc/"+str(pid)+"/statm").readline().split()[1])*PAGESIZE
if os.path.exists("/proc/"+str(pid)+"/smaps"): #stat
for line in open("/proc/"+str(pid)+"/smaps").readlines(): #open
if line.startswith("Shared"):
Shared_lines.append(line)
elif line.startswith("Private"):
Private_lines.append(line)
elif line.startswith("Pss"):
have_pss=1
Pss_lines.append(line)
Shared=sum([int(line.split()[1]) for line in Shared_lines])
Private=sum([int(line.split()[1]) for line in Private_lines])
#Note Shared + Private = Rss above
#The Rss in smaps includes video card mem etc.
if have_pss:
pss_adjust=0.5 #add 0.5KiB as this average error due to trunctation
Pss=sum([float(line.split()[1])+pss_adjust for line in Pss_lines])
Shared = Pss - Private
elif (2,6,1) <= kv <= (2,6,9):
Shared=0 #lots of overestimation, but what can we do?
Private = Rss
else:
Shared=int(open("/proc/"+str(pid)+"/statm").readline().split()[2])
Shared*=PAGESIZE
Private = Rss - Shared
return (Private, Shared)

def getCmdName(pid):
cmd = file("/proc/%d/status" % pid).readline()[6:-1]
exe = os.path.basename(os.path.realpath("/proc/%d/exe" % pid))
if exe.startswith(cmd):
cmd=exe #show non truncated version
#Note because we show the non truncated name
#one can have separated programs as follows:
#584.0 KiB + 1.0 MiB = 1.6 MiB mozilla-thunder (exe -> bash)
# 56.0 MiB + 22.2 MiB = 78.2 MiB mozilla-thunderbird-bin
return cmd

cmds={}
shareds={}
count={}
for pid in os.listdir("/proc/"):
try:
pid = int(pid) #note Thread IDs not listed in /proc/ which is good
if pid == our_pid: continue
except:
continue
try:
cmd = getCmdName(pid)
except:
#permission denied or
#kernel threads don't have exe links or
#process gone
continue
try:
private, shared = getMemStats(pid)
except:
continue #process gone
if shareds.get(cmd):
if have_pss: #add shared portion of PSS together
shareds[cmd]+=shared
elif shareds[cmd] < shared: #just take largest shared val
shareds[cmd]=shared
else:
shareds[cmd]=shared
cmds[cmd]=cmds.setdefault(cmd,0)+private
if count.has_key(cmd):
count[cmd] += 1
else:
count[cmd] = 1

#Add shared mem for each program
total=0
for cmd in cmds.keys():
cmds[cmd]=cmds[cmd]+shareds[cmd]
total+=cmds[cmd] #valid if PSS available

sort_list = cmds.items()
sort_list.sort(lambda x,y:cmp(x[1],y[1]))
sort_list=filter(lambda x:x[1],sort_list) #get rid of zero sized processes

#The following matches "du -h" output
#see also human.py
def human(num, power="Ki"):
powers=["Ki","Mi","Gi","Ti"]
while num >= 1000: #4 digits
num /= 1024.0
power=powers[powers.index(power)+1]
return "%.1f %s" % (num,power)

def cmd_with_count(cmd, count):
if count>1:
return "%s (%u)" % (cmd, count)
else:
return cmd

print " Private + Shared = RAM used\tProgram \n"
for cmd in sort_list:
print "%8sB + %8sB = %8sB\t%s" % (human(cmd[1]-shareds[cmd[0]]),
human(shareds[cmd[0]]), human(cmd[1]),
cmd_with_count(cmd[0], count[cmd[0]]))
if have_pss:
print "-" * 33
print " " * 24 + "%8sB" % human(total)
print "=" * 33
print "\n Private + Shared = RAM used\tProgram \n"

#Warn of possible inaccuracies
#2 = accurate & can total
#1 = accurate only considering each process in isolation
#0 = some shared mem not reported
#-1= all shared mem not reported
def shared_val_accuracy():
"""http://wiki.apache.org/spamassassin/TopSharedMemoryBug"""
if kv[:2] == (2,4):
if open("/proc/meminfo").read().find("Inact_") == -1:
return 1
return 0
elif kv[:2] == (2,6):
if os.path.exists("/proc/"+str(os.getpid())+"/smaps"):
if open("/proc/"+str(os.getpid())+"/smaps").read().find("Pss:")!=-1:
return 2
else:
return 1
if (2,6,1) <= kv <= (2,6,9):
return -1
return 0
else:
return 1

vm_accuracy = shared_val_accuracy()
if vm_accuracy == -1:
sys.stderr.write(
"Warning: Shared memory is not reported by this system.\n"
)
sys.stderr.write(
"Values reported will be too large, and totals are not reported\n"
)
elif vm_accuracy == 0:
sys.stderr.write(
"Warning: Shared memory is not reported accurately by this system.\n"
)
sys.stderr.write(
"Values reported could be too large, and totals are not reported\n"
)
elif vm_accuracy == 1:
sys.stderr.write(
"Warning: Shared memory is slightly over-estimated by this system\n"
"for each program, so totals are not reported.\n"
)
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