From: Sebastien Godard <sysstat@orange.fr>
Date: Fri, 12 Nov 2010 15:44:21 +0000 (+0100)
Subject: sar now tells sadc to read only the necessary groups of activities.
X-Git-Tag: v9.1.7~11
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=1dd72028c319181445030c94e69f77e14d7e5a00;p=sysstat

sar now tells sadc to read only the necessary groups of activities.

We noticed that a simple command like "sar 0" had a small delay before
displaying the CPU statsitics since system startup. This was because
in every case sar called sadc with option -S ALL resulting in all
possible activities being read.
Now, except if sar's option -o is used (in which case all possible
activities will still be read), sar tells sadc to read only the groups
of activities that include those that will be displayed on screen.
---

diff --git a/CHANGES b/CHANGES
index 64e9cbc..6871da8 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,8 @@
 Changes:
 
 xxxx/xx/xx: Version 9.1.7 - Sebastien Godard (sysstat <at> orange.fr)
+	* sar now tells sadc to read only the necessary groups of
+	  activities.
 	* sar manual page updated.
 
 2010/11/10: Version 9.1.6 - Sebastien Godard (sysstat <at> orange.fr)
diff --git a/sadc.c b/sadc.c
index 9a16b5c..54f1c7d 100644
--- a/sadc.c
+++ b/sadc.c
@@ -164,14 +164,24 @@ void parse_sadc_S_option(char *argv[], int opt)
 			 * Although undocumented, option -S followed by a numerical value
 			 * enables the user to select each activity that should be
 			 * collected. "-S 0" unselects all activities but CPU.
+			 * A value greater than 255 enables the user to select groups
+			 * of activities.
 			 */
 			int act_id;
 
 			act_id = atoi(argv[opt]);
-			if ((act_id < 0) || (act_id > NR_ACT)) {
+			if (act_id > 255) {
+				act_id >>= 8;
+				for (i = 0; i < NR_ACT; i++) {
+					if (act[i]->group & act_id) {
+						act[i]->options |= AO_COLLECTED;
+					}
+				}
+			}
+			else if ((act_id < 0) || (act_id > NR_ACT)) {
 				usage(argv[0]);
 			}
-			if (!act_id) {
+			else if (!act_id) {
 				/* Unselect all activities but CPU */
 				for (i = 0; i < NR_ACT; i++) {
 					act[i]->options &= ~AO_COLLECTED;
diff --git a/sar.c b/sar.c
index c9fc5b6..9fcc0f7 100644
--- a/sar.c
+++ b/sar.c
@@ -1057,7 +1057,7 @@ void read_stats(void)
  */
 int main(int argc, char **argv)
 {
-	int opt = 1, args_idx = 2;
+	int i, opt = 1, args_idx = 2;
 	int fd[2];
 	char from_file[MAX_FILE_LEN], to_file[MAX_FILE_LEN];
 	char ltemp[20];
@@ -1322,13 +1322,35 @@ int main(int argc, char **argv)
 
 		/* Flags to be passed to sadc */
 		salloc(args_idx++, "-z");
-		salloc(args_idx++, "-S");
-		salloc(args_idx++, K_ALL);
-
-		/* Outfile arg */
+		
+		/* Writing data to a file (option -o) */
 		if (to_file[0]) {
+			/* Collect all possible activities (option -S ALL for sadc) */
+			salloc(args_idx++, "-S");
+			salloc(args_idx++, K_ALL);
+			/* Outfile arg */
 			salloc(args_idx++, to_file);
 		}
+		else {
+			/*
+			 * If option -o hasn't been used, then tell sadc
+			 * to collect only activities that will be displayed.
+			 */
+			int act_id = 0;
+			
+			for (i = 0; i < NR_ACT; i++) {
+				if (IS_SELECTED(act[i]->options)) {
+					act_id |= act[i]->group;
+				}
+			}
+			if (act_id) {
+				act_id <<= 8;
+				snprintf(ltemp, 19, "%d", act_id);
+				ltemp[19] = '\0';
+				salloc(args_idx++, "-S");
+				salloc(args_idx++, ltemp);
+			}
+		}
 
 		/* Last arg is NULL */
 		args[args_idx] = NULL;