/dev/shm

[Dan Nelson]

In the last episode (Jul 07), Matthias Andree said:
> Marcin Dalecki schrieb am 2003-07-07:
> > Matthias Andree wrote:
> > >Update your Linux top or run fewer processes on it then. :->
> > 
> > You know that file system name lookup is one of the most expensive
> > system calls under UNIX?
> 
> So what? If you don't like the interface because it does ever so
> expensive file system lookups (I wonder what's so expensive if no
> disk drive latencies are involved), suggest a better one and donate
> an implementation.
> 
> I'm sure I'd find disadvantages of non-Linux top if I only cared to
> look. I don't. It works when I need it, it's not in my way otherwise,
> that's as much as I care.

There is already a functional non-procfs implementation that has been
around long before procps top: groupsys top 3.5b12 (i.e. the top that
all other non-Linux systems use) compiles fine on even the newest Linux
kernels with the attached patch.  It's one of the first things I build
on a new Linux box.  Procps top is way too slow; it takes a full 5
seconds just for the first screen refresh on a mostly-idle box with 400
processes.  groupsys top is basically instantaneous.  And don't think
about accidentally hitting a cursor or function key which running
procps top; it doesn't even use curses, so it beeps and waits 2 seconds
for each character in the escape sequence :)

-- 
	Dan Nelson
	dnelson at allantgroup.com
-------------- next part --------------
diff -burp top-3.5beta12/display.c top-3.5beta12-l/display.c
--- top-3.5beta12/display.c	Thu Sep 12 15:24:39 1996
+++ top-3.5beta12-l/display.c	Mon Apr 29 12:45:54 2002
@@ -931,12 +931,12 @@ register char **pp;
 static void summary_format(str, numbers, names)
 
 char *str;
-int *numbers;
+unsigned int *numbers;
 register char **names;
 
 {
     register char *p;
-    register int num;
+    register unsigned int num;
     register char *thisname;
     register int useM = No;
 
@@ -946,6 +946,8 @@ register char **names;
     {
 	/* get the number to format */
 	num = *numbers++;
+
+/* fprintf(stderr,"%lu\n",num); */
 
 	/* display only non-zero numbers */
 	if (num > 0)
diff -burp top-3.5beta12/machine/m_linux.c top-3.5beta12-l/machine/m_linux.c
--- top-3.5beta12/machine/m_linux.c	Fri Jan 15 08:42:07 1999
+++ top-3.5beta12-l/machine/m_linux.c	Mon Apr 29 12:45:54 2002
@@ -36,7 +36,8 @@
 
 #include <sys/param.h>		/* for HZ */
 #include <asm/page.h>		/* for PAGE_SHIFT */
-#include <linux/tasks.h>	/* for NR_TASKS */
+/* #include <linux/tasks.h> */	/* for NR_TASKS */
+#define NR_TASKS 8192
 
 #if 0
 #include <linux/proc_fs.h>	/* for PROC_SUPER_MAGIC */
@@ -139,7 +140,7 @@ static struct top_proc **nextactive;
 
 static int cpu_states[NCPUSTATES];
 static int process_states[NPROCSTATES];
-static int memory_stats[NMEMSTATS];
+static unsigned int memory_stats[NMEMSTATS];
 
 /* usefull macros */
 #define bytetok(x)	(((x) + 512) >> 10)
diff -burp top-3.5beta12/screen.c top-3.5beta12-l/screen.c
--- top-3.5beta12/screen.c	Wed Dec 15 11:44:10 1993
+++ top-3.5beta12-l/screen.c	Mon Apr 29 12:45:54 2002
@@ -71,7 +71,6 @@ char *start_standout;
 char *end_standout;
 char *terminal_init;
 char *terminal_end;
-short ospeed;
 
 #ifdef SGTTY
 static struct sgttyb old_settings;
diff -burp top-3.5beta12/utils.c top-3.5beta12-l/utils.c
--- top-3.5beta12/utils.c	Mon Jun  1 12:58:17 1998
+++ top-3.5beta12-l/utils.c	Mon Apr 29 12:45:54 2002
@@ -59,27 +59,16 @@ char *str;
 
 char *itoa(val)
 
-register int val;
+register unsigned int val;
 
 {
-    register char *ptr;
     static char buffer[16];	/* result is built here */
     				/* 16 is sufficient since the largest number
 				   we will ever convert will be 2^32-1,
 				   which is 10 digits. */
 
-    ptr = buffer + sizeof(buffer);
-    *--ptr = '\0';
-    if (val == 0)
-    {
-	*--ptr = '0';
-    }
-    else while (val != 0)
-    {
-	*--ptr = (val % 10) + '0';
-	val /= 10;
-    }
-    return(ptr);
+	sprintf(buffer,"%lu",val);
+	return buffer;
 }
 
 /*
@@ -437,7 +426,7 @@ long seconds;
 
 char *format_k(amt)
 
-int amt;
+unsigned int amt;
 
 {
     static char retarray[NUM_STRINGS][16];