snow: only create n_cpus fragments

Since snow_context_t needs another member anyways, stick n_cpus in there
to inform the fragmenter of precisely how many fragments to make.

This renderer doesn't benefit from tiling or any such locality, so it uses
the slice fragmenter and really only benefits from as many fragments as there
are CPUs.  Any additional fragments is just wasted fragmenting overhead.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/modules/snow/snow.c b/src/modules/snow/snow.c
index 3e6331a..2de4d76 100644
--- a/src/modules/snow/snow.c
+++ b/src/modules/snow/snow.c
@@ -15,7 +15,7 @@ typedef union snow_seed_t {
 } snow_seed_t;
 
 typedef struct snow_context_t {
-	int		foo;		/* make the compiler happy */
+	unsigned	n_cpus;
 	snow_seed_t	seeds[];
 } snow_context_t;
 
@@ -31,6 +31,8 @@ static void * snow_create_context(unsigned n_cpus)
 	for (unsigned i = 0; i < n_cpus; i++)
 		ctxt->seeds[i].seed = rand();
 
+	ctxt->n_cpus = n_cpus;
+
 	return ctxt;
 }
 
@@ -43,7 +45,9 @@ static void snow_destroy_context(void *context)
 
 static int snow_fragmenter(void *context, const fb_fragment_t *fragment, unsigned number, fb_fragment_t *res_fragment)
 {
-	return fb_fragment_slice_single(fragment, 32, number, res_fragment);
+	snow_context_t	*ctxt = context;
+
+	return fb_fragment_slice_single(fragment, ctxt->n_cpus, number, res_fragment);
 }