From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <1de2c7c96eb8168c5d4c800fb3dba008@vitanuova.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] Re: patch/list sorry/proc-mtime
Date: Thu, 30 Mar 2006 18:24:20 +0100
From: rog@vitanuova.com
In-Reply-To: <509071940603300542v4d79c76pa797c8d73a3cfd5d@mail.gmail.com>
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i was about to say that i'd find it useful if the atime of /proc/n
reflected the last run time of a process, to make it easier to find
cpu hogs, but russ's point about ls -lt /proc's uselessness is bang
on.

so, by way of a little script to help with the above problem, which
bugs me every so often, here's "hogs", a poor man's replacement for
unix's "top" - it's like ps except that it sorts the processes by the
amount of time they've used over the last t (default 1) seconds.

it displays percentage of time used over the sample time (this might
be >100% with multiple cpus), and combines user, syscall and child
time into the second time column (to make it easier to find processes
that spawn lots of transient cpu-eating processes but don't do much
themselves); otherwise the output format is the same as for ps(1).

YMMV - i imagine others have similar scripts.

cat >$home/bin/rc/hogs <<'EOF'
#!/bin/rc
# usage: hogs [sampletime]
t=1
if(! ~ $#* 0){
	t = $1
}
{
	cd /proc
	for(i in [0-9]*){
		cat $i/status && echo $i
	}
	echo
	sleep $t
	for(i in [0-9]*){
		cat $i/status && echo $i
	}
} | awk '
	phase == 0 && /./ {
		t0[$13] = $4+$5+$7+$8;
		rt0[$13] = $6
		next
	}
	phase == 0 && /^$/ {
		phase = 1;
		next
	}
	phase != 0 {
		t1[$13] = $4+$5+$7+$8
		rt1[$13] = $6
		line[$13] = $0
	}
	END {
		for(i in line){
			n = split(line[i], p, " ");
			dt = ((t1[i] - t0[i] + 0.0) / (rt1[i] - rt0[i])) * 100
			utime = (p[4]+p[4]+p[7]+p[8]) / 1000;
			size = p[9];
			if(dt >= 1 || utime >= 1){
				printf("%-10s %8s %3d%% %4d.%.2d %7dK %-8.8s %s\n",
					p[2],
					i,
					dt,
					utime/60, utime%60,
					size,
					p[3],
					p[1]);
			}
		}
	}' |
	sort +2rn -3rn +3rn |
	sed 's/(^[^ ]+ +[0-9]+ +[0-9]+% +[0-9]+)\./\1:/'
EOF