perf_counter: kerneltop: mmap_pages argument

provide a knob to set the number of mmap data pages.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Orig-LKML-Reference: <20090325113317.104545398@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 25 insertions, 6 deletions

diff --git a/Documentation/perf_counter/kerneltop.c b/Documentation/perf_counter/kerneltop.c
index 7ebde7a336c6..3e45bf6591b2 100644
--- a/Documentation/perf_counter/kerneltop.c
+++ b/Documentation/perf_counter/kerneltop.c
@@ -178,6 +178,7 @@ static int			nr_cpus				=  0;
 static int                      nmi                             =  1;
 static int                      group                           =  0;
 static unsigned int             page_size;
+static unsigned int             mmap_pages                      =  4;
 
 static char                     *vmlinux;
 
@@ -326,6 +327,7 @@ static void display_help(void)
         " -x path   --vmlinux=<path>   # the vmlinux binary, required for -s use\n"
         " -z        --zero             # zero counts after display\n"
         " -D        --dump_symtab      # dump symbol table to stderr on startup\n"
+        " -m pages  --mmap_pages=<pages> # number of mmap data pages\n"
         );
 
         exit(0);
@@ -732,7 +734,9 @@ static int read_symbol(FILE *in, struct sym_entry *s)
         /* Tag events to be skipped. */
         if (!strcmp("default_idle", s->sym) || !strcmp("cpu_idle", s->sym))
                 s->skip = 1;
-        if (!strcmp("enter_idle", s->sym) || !strcmp("exit_idle", s->sym))
+        else if (!strcmp("enter_idle", s->sym) || !strcmp("exit_idle", s->sym))
+                s->skip = 1;
+        else if (!strcmp("mwait_idle", s->sym))
                 s->skip = 1;
 
         if (filter_match == 1) {
@@ -1042,9 +1046,10 @@ static void process_options(int argc, char *argv[])
                         {"symbol",      required_argument,      NULL, 's'},
                         {"stat",        no_argument,            NULL, 'S'},
                         {"zero",        no_argument,            NULL, 'z'},
+                        {"mmap_pages",  required_argument,      NULL, 'm'},
                         {NULL,          0,                      NULL,  0 }
                 };
-                int c = getopt_long(argc, argv, "+:ac:C:d:De:f:g:hn:p:s:Sx:z",
+                int c = getopt_long(argc, argv, "+:ac:C:d:De:f:g:hn:m:p:s:Sx:z",
                                     long_options, &option_index);
                 if (c == -1)
                         break;
@@ -1081,6 +1086,7 @@ static void process_options(int argc, char *argv[])
                 case 'S': run_perfstat                  =              1; break;
                 case 'x': vmlinux                       = strdup(optarg); break;
                 case 'z': zero                          =              1; break;
+                case 'm': mmap_pages                    =   atoi(optarg); break;
                 default: error = 1; break;
                 }
         }
@@ -1134,17 +1140,30 @@ repeat:
         return head;
 }
 
+struct timeval last_read, this_read;
+
 static void mmap_read(struct mmap_data *md)
 {
         unsigned int head = mmap_read_head(md);
         unsigned int old = md->prev;
         unsigned char *data = md->base + page_size;
 
+        gettimeofday(&this_read, NULL);
+
         if (head - old > md->mask) {
-                printf("ERROR: failed to keep up with mmap data\n");
-                exit(-1);
+                struct timeval iv;
+                unsigned long msecs;
+
+                timersub(&this_read, &last_read, &iv);
+                msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
+
+                fprintf(stderr, "WARNING: failed to keep up with mmap data.  Last read %lu msecs ago.\n", msecs);
+
+                old = head;
         }
 
+        last_read = this_read;
+
         for (; old != head;) {
                 __u64 *ptr = (__u64 *)&data[old & md->mask];
                 old += sizeof(__u64);
@@ -1220,8 +1239,8 @@ int main(int argc, char *argv[])
 
                         mmap_array[i][counter].counter = counter;
                         mmap_array[i][counter].prev = 0;
-                        mmap_array[i][counter].mask = 2*page_size - 1;
-                        mmap_array[i][counter].base = mmap(NULL, 3*page_size,
+                        mmap_array[i][counter].mask = mmap_pages*page_size - 1;
+                        mmap_array[i][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
                                         PROT_READ, MAP_SHARED, fd[i][counter], 0);
                         if (mmap_array[i][counter].base == MAP_FAILED) {
                                 printf("kerneltop error: failed to mmap with %d (%s)\n",