nfsstat: add -D/--diff-stat

	Add -D/--diff-stat: instead of immediately displaying total
collected NFS stats and exiting, nfsstat will take a snapshot of current
statistics and pause until the user hits ^C, at which point it takes a
second snapshot and then prints out the difference of the two; i.e.,
only the statistics collected during the pause.

Signed-off-by: David M. Richter <richterd@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>

diff --git a/utils/nfsstat/nfsstat.c b/utils/nfsstat/nfsstat.c
index bd105f5d7b1b5d056cbec13966f0ccaaf38c1326..d9d119eb5f81ddb3c898c72fba618a363556df67 100644 (file)
--- a/utils/nfsstat/nfsstat.c
+++ b/utils/nfsstat/nfsstat.c
@@ -20,6 +20,8 @@
 #include <string.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <signal.h>
+#include <time.h>
 
 #define MAXNRVALS      32
 
@@ -161,6 +163,11 @@ static int         mounts(const char *);
 
 static void            get_stats(const char *, statinfo *, int *, int, const char *);
 static int             has_stats(const unsigned int *);
+static void            copy_stats(statinfo *, statinfo *);
+static void            diff_stats(statinfo *, statinfo *);
+static void            unpause(int);
+
+static time_t          starttime;
 
 #define PRNT_CALLS     0x0001
 #define PRNT_RPC       0x0002
@@ -199,6 +206,7 @@ void usage(char *name)
   -v, --verbose, --all\tSame as '-o all'\n\
   -r, --rpc\t\tShow RPC statistics\n\
   -n, --nfs\t\tShow NFS statistics\n\
+  -D, --diff-stat\tSaves stats, pauses, diffs current and saved\n\
   --version\t\tShow program version\n\
   --help\t\tWhat you just did\n\
 \n", name);
@@ -219,6 +227,7 @@ static struct option longopts[] =
        { "zero", 0, 0, 'z' },
        { "help", 0, 0, '\1' },
        { "version", 0, 0, '\2' },
+       { "diff-stat", 0, 0, 'D' },
        { NULL, 0, 0, 0 }
 };
 
@@ -228,16 +237,22 @@ main(int argc, char **argv)
        int             opt_all = 0,
                        opt_srv = 0,
                        opt_clt = 0,
-                       opt_prt = 0;
+                       opt_prt = 0,
+                       opt_diffstat = 0;
        int             c;
        char           *progname;
 
+       struct sigaction act = {
+               .sa_handler = unpause,
+               .sa_flags = SA_ONESHOT,
+       };
+
        if ((progname = strrchr(argv[0], '/')))
                progname++;
        else
                progname = argv[0];
 
-       while ((c = getopt_long(argc, argv, "234acmno:vrsz\1\2", longopts, NULL)) != EOF) {
+       while ((c = getopt_long(argc, argv, "234acmno:Dvrsz\1\2", longopts, NULL)) != EOF) {
                switch (c) {
                case 'a':
                        fprintf(stderr, "nfsstat: nfs acls are not yet supported.\n");
@@ -267,6 +282,9 @@ main(int argc, char **argv)
                                return 2;
                        }
                        break;
+               case 'D':
+                       opt_diffstat = 1;
+                       break;
                case '2':
                case '3':
                case '4':
@@ -327,6 +345,29 @@ main(int argc, char **argv)
        if (opt_clt)
                get_stats(NFSCLTSTAT, cltinfo, &opt_clt, opt_srv, "Client");
 
+       /* save stat snapshots; wait for signal; then diff current and saved stats */
+       if (opt_diffstat) {
+               starttime = time(NULL);
+               printf("Collecting statistics; press CTRL-C to view results from interval (i.e., from pause to CTRL-C).\n");
+               if (opt_srv)
+                       copy_stats(srvinfo_tmp, srvinfo);
+               if (opt_clt)
+                       copy_stats(cltinfo_tmp, cltinfo);
+               if (sigaction(SIGINT, &act, NULL) != 0) {
+                       fprintf(stderr, "Error: couldn't register for signal and pause.\n");
+                       return 1;
+               }
+               pause();
+               if (opt_srv) {
+                       get_stats(NFSSRVSTAT, srvinfo, &opt_srv, opt_clt, "Server");
+                       diff_stats(srvinfo, srvinfo_tmp);
+               }
+               if (opt_clt) {
+                       get_stats(NFSCLTSTAT, cltinfo, &opt_clt, opt_srv, "Client");
+                       diff_stats(cltinfo, cltinfo_tmp);
+               }
+       }
+
        if (opt_srv) {
                if (opt_prt & PRNT_NET) {
                        print_numbers(
@@ -601,3 +642,51 @@ has_stats(const unsigned int *info)
 {
        return (info[0] && info[info[0] + 1] != info[0]);
 }
+
+/* clone 'src' to 'dest' */
+static void
+copy_stats(struct statinfo *dest, struct statinfo *src)
+{
+       int i, j;
+
+       for (i = 0; src[i].tag; i++) {
+               dest[i].tag = src[i].tag;
+               dest[i].nrvals = src[i].nrvals;
+               for (j = 0; j < dest[i].nrvals; j++)
+                       dest[i].valptr[j] = src[i].valptr[j];
+       }
+}
+
+/*
+ * take the difference of each individual stat value in 'new' and 'old'
+ * and store the results back into 'new'
+ */
+static void
+diff_stats(struct statinfo *new, struct statinfo *old)
+{
+       int i, j, is_srv, should_diff;
+
+       is_srv = (new == srvinfo);
+       for (i = 0; old[i].tag; i++) {
+               for (j = 0; j < new[i].nrvals; j++) {
+                       /* skip items in valptr that shouldn't be changed */
+                       should_diff = (i < (3 + is_srv) || j > 0);
+                       if (should_diff)
+                               new[i].valptr[j] -= old[i].valptr[j];
+               }
+       }
+}
+
+static void
+unpause(int sig)
+{
+       double time_diff;
+       int minutes, seconds;
+       time_t endtime;
+
+       endtime = time(NULL);
+       time_diff = difftime(endtime, starttime);
+       minutes = time_diff / 60;
+       seconds = (int)time_diff % 60;
+       printf("Signal received; displaying (only) statistics gathered over the last %d minutes, %d seconds:\n\n", minutes, seconds);
+}