Edit the interrupt name strings to shorten them. This is believed to

only affect amd64 and i386.  alpha uses "intr N" instead of "irqN" and
mostly has no device names.  ia64 uses only device names.

- Edit interrupt names once after they are read from the kernel and not
  every time they are displayed.
- Discard bogus trailing spaces so that the next step doesn't move things
  to oblivion.
- If an interrupt name starts with "irqN:" (as it usually does in on
  amd64 and i386), then move "irqN" to the end and strip ":", since we
  have no space for the ":" and don't want to start descriptions with
  "N" after stripping "irq" in the next step (since "N" would look like
  a count).  This step may need reworking for interrupt names containing
  several device names -- then moving the irq number to the end would
  lose it instead of losing some device names.
- Remove "irq" from an interrupt name if and only if the original name is
  too long to display.

usr.bin/systat/vmstat.c

@@ -207,7 +207,7 @@ closekre(w)
 int
 initkre()
 {
-	char *intrnamebuf, *cp;
+	char *cp, *cp1, *cp2, *intrnamebuf, *nextcp;
 	int i;
 	size_t sz;
 
@@ -249,8 +249,39 @@ initkre()
 			return(0);
 		}
 		for (cp = intrnamebuf, i = 0; i < nintr; i++) {
+			nextcp = cp + strlen(cp) + 1;
+
+			/* Discard trailing spaces. */
+			for (cp1 = nextcp - 1; cp1 > cp && *(cp1 - 1) == ' '; )
+				*--cp1 = '\0';
+
+			/* Convert "irqN: name" to "name irqN". */
+			if (strncmp(cp, "irq", 3) == 0) {
+				cp1 = cp + 3;
+				while (isdigit((u_char)*cp1))
+					cp1++;
+				if (cp1 != cp && *cp1 == ':' &&
+				    *(cp1 + 1) == ' ') {
+					*cp1 = '\0';
+					cp1 = cp1 + 2;
+					cp2 = strdup(cp);
+					bcopy(cp1, cp, strlen(cp1) + 1);
+					strcat(cp, " ");
+					strcat(cp, cp2);
+					free(cp2);
+				}
+			}
+
+			/*
+			 * Convert "name irqN" to "name N" if the former is
+			 * longer than the field width.
+			 */
+			if ((cp1 = strstr(cp, "irq")) != NULL &&
+			    strlen(cp) > 10)
+				bcopy(cp1 + 3, cp1, strlen(cp1 + 3) + 1);
+
 			intrname[i] = cp;
-			cp += strlen(cp) + 1;
+			cp = nextcp;
 		}
 		nextintsrow = INTSROW + 2;
 		allocinfo(&s);