A_NET_SOFT: Use CPU id from /proc/net/softnet_stat

CPU id has been added as a new column in /proc/net/softnet_stat in
kernel 5.10. Use it to map data to their corresponding CPU.
See #315.

Signed-off-by: Sebastien GODARD <sysstat@users.noreply.github.com>

diff --git a/rd_stats.c b/rd_stats.c
index ad3aec125950d7413831287383d8e66a344c83da..bcaa890bf7d25e31bd37608a84667548faa8fa51 100644 (file)
--- a/rd_stats.c
+++ b/rd_stats.c
@@ -2803,9 +2803,9 @@ int read_softnet(struct stats_softnet *st_softnet, __nr_t nr_alloc,
                 unsigned char online_cpu_bitmap[])
 {
        FILE *fp;
-       struct stats_softnet *st_softnet_i;
+       struct stats_softnet *st_softnet_i, st_softnet_read;
        char line[1024];
-       int cpu = 1, rc = 1;
+       int cpu = 1, rc = 1, i, cpu_id;
 
        /* Open /proc/net/softnet_stat file */
        if ((fp = fopen(NET_SOFTNET, "r")) == NULL)
@@ -2813,8 +2813,23 @@ int read_softnet(struct stats_softnet *st_softnet, __nr_t nr_alloc,
 
        while (fgets(line, sizeof(line), fp) != NULL) {
 
-               while ((!(online_cpu_bitmap[(cpu - 1) >> 3] & (1 << ((cpu - 1) & 0x07)))) && (cpu < nr_alloc)) {
-                       cpu++;
+               i = sscanf(line, "%x %x %x %*x %*x %*x %*x %*x %*x %x %x %*x %x",
+                          &(st_softnet_read.processed),
+                          &(st_softnet_read.dropped),
+                          &(st_softnet_read.time_squeeze),
+                          &(st_softnet_read.received_rps),
+                          &(st_softnet_read.flow_limit),
+                          &cpu_id);
+
+               if (i == 6) {
+                       /* Corresponding CPU read in file */
+                       cpu = cpu_id + 1;
+               }
+               else {
+                       /* cpu_id not present in file */
+                       while ((!(online_cpu_bitmap[(cpu - 1) >> 3] & (1 << ((cpu - 1) & 0x07)))) && (cpu < nr_alloc)) {
+                               cpu++;
+                       }
                }
 
                if (cpu >= nr_alloc) {
@@ -2823,12 +2838,7 @@ int read_softnet(struct stats_softnet *st_softnet, __nr_t nr_alloc,
                }
 
                st_softnet_i = st_softnet + cpu++;
-               sscanf(line, "%x %x %x %*x %*x %*x %*x %*x %*x %x %x",
-                      &st_softnet_i->processed,
-                      &st_softnet_i->dropped,
-                      &st_softnet_i->time_squeeze,
-                      &st_softnet_i->received_rps,
-                      &st_softnet_i->flow_limit);
+               *st_softnet_i = st_softnet_read;
        }
 
        fclose(fp);