[PATCH] swsusp: add write-speed instrumentation

Add some instrumentation to the swsusp writeout code to show what bandwidth
we're achieving.

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

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index f1dd146bd64dd97237e5d4fb5d08cefaf3712158..79b66e734bdb1a195edb461a64d23e882cc91451 100644 (file)
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -146,6 +146,26 @@ static void release_swap_writer(struct swap_map_handle *handle)
        handle->bitmap = NULL;
 }
 
+static void 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);
+}
+
 static int get_swap_writer(struct swap_map_handle *handle)
 {
        handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
@@ -206,17 +226,21 @@ static int flush_swap_writer(struct swap_map_handle *handle)
 
 static int save_image(struct swap_map_handle *handle,
                       struct snapshot_handle *snapshot,
-                      unsigned int nr_pages)
+                      unsigned int nr_to_write)
 {
        unsigned int m;
        int ret;
        int error = 0;
+       int nr_pages;
+       struct timeval start;
+       struct timeval stop;
 
-       printk("Saving image data pages (%u pages) ...     ", nr_pages);
-       m = nr_pages / 100;
+       printk("Saving image data pages (%u pages) ...     ", nr_to_write);
+       m = nr_to_write / 100;
        if (!m)
                m = 1;
        nr_pages = 0;
+       do_gettimeofday(&start);
        do {
                ret = snapshot_read_next(snapshot, PAGE_SIZE);
                if (ret > 0) {
@@ -228,8 +252,10 @@ static int save_image(struct swap_map_handle *handle,
                        nr_pages++;
                }
        } while (ret > 0);
+       do_gettimeofday(&stop);
        if (!error)
                printk("\b\b\b\bdone\n");
+       show_speed(&start, &stop, nr_to_write, "Wrote");
        return error;
 }