[PATCH] swsusp: Measure memory shrinking time

Make swsusp measure and print the time needed to shrink memory during the
suspend.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@suspend2.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 33 insertions, 0 deletions

diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index 68de5c1dbd78..aa31432bbd97 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -49,6 +49,7 @@
 #include <linux/bootmem.h>
 #include <linux/syscalls.h>
 #include <linux/highmem.h>
+#include <linux/time.h>
 
 #include "power.h"
 
@@ -164,6 +165,34 @@ void free_all_swap_pages(int swap, struct bitmap_page *bitmap)
 }
 
 /**
+ *      swsusp_show_speed - print the time elapsed between two events represented by
+ *      @start and @stop
+ *
+ *      @nr_pages -     number of pages processed between @start and @stop
+ *      @msg -          introductory message to print
+ */
+
+void swsusp_show_speed(struct timeval *start, struct timeval *stop,
+                        unsigned nr_pages, char *msg)
+{
+        s64 elapsed_centisecs64;
+        int centisecs;
+        int k;
+        int kps;
+
+        elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
+        do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
+        centisecs = elapsed_centisecs64;
+        if (centisecs == 0)
+                centisecs = 1;  /* avoid div-by-zero */
+        k = nr_pages * (PAGE_SIZE / 1024);
+        kps = (k * 100) / centisecs;
+        printk("%s %d kbytes in %d.%02d seconds (%d.%02d MB/s)\n", msg, k,
+                        centisecs / 100, centisecs % 100,
+                        kps / 1000, (kps % 1000) / 10);
+}
+
+/**
  *      swsusp_shrink_memory -  Try to free as much memory as needed
  *
  *      ... but do not OOM-kill anyone
@@ -187,8 +216,10 @@ int swsusp_shrink_memory(void)
         unsigned long pages = 0;
         unsigned int i = 0;
         char *p = "-\\|/";
+        struct timeval start, stop;
 
         printk("Shrinking memory...  ");
+        do_gettimeofday(&start);
         do {
                 long size, highmem_size;
 
@@ -222,7 +253,9 @@ int swsusp_shrink_memory(void)
                 }
                 printk("\b%c", p[i++%4]);
         } while (tmp > 0);
+        do_gettimeofday(&stop);
         printk("\bdone (%lu pages freed)\n", pages);
+        swsusp_show_speed(&start, &stop, pages, "Freed");
 
         return 0;
 }