Changeset 4759

Timestamp:

09/05/07 10:19:09 (6 years ago)

Author:

khali

Message:

Renumber the features linearly, so that feature number N is at
position N in the array. This allows for O(1) look-ups, as opposed
to O(N) before. This makes sensors_lookup_feature_nr() 2.4 times
faster in my real-world tests, resulting in a 6% performance boost
on average in the runtime part of "sensors".

Location:

lm-sensors/branches/lm-sensors-3.0.0/lib

Files:

• access.c (modified) (1 diff)
• sysfs.c (modified) (1 diff)

lm-sensors/branches/lm-sensors-3.0.0/lib/access.c

@@ -93 +93 @@
                                                       int feature)
 {
-        int i, j;
-        const sensors_chip_feature *features;
+        int i;
 
         for (i = 0; i < sensors_proc_chips_count; i++)
                 if (sensors_match_chip(&sensors_proc_chips[i].chip, chip)) {
-                        features = sensors_proc_chips[i].feature;
-                        for (j = 0; features[j].data.name; j++)
-                                if (features[j].data.number == feature)
-                                        return features + j;
+                        return sensors_proc_chips[i].feature + feature;
                 }
         return NULL;

lm-sensors/branches/lm-sensors-3.0.0/lib/sysfs.c

@@ -176 +176 @@
                         dyn_features[fnum] = features[i];
                         fnum++;
+                }
+        }
+
+        /* Renumber the features linearly, so that feature number N is at
+           position N in the array. This allows for O(1) look-ups. */
+        for (i = 0; i < fnum; i++) {
+                int j, old;
+
+                old = dyn_features[i].data.number;
+                dyn_features[i].data.number = i;
+                for (j = i + 1;
+                     j < fnum && dyn_features[j].data.mapping != SENSORS_NO_MAPPING;
+                     j++) {
+                        if (dyn_features[j].data.mapping == old)
+                                dyn_features[j].data.mapping = i;
                 }
         }