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authorTobias Klauser <tklauser@distanz.ch>2015-10-29 15:58:05 +0100
committerTobias Klauser <tklauser@distanz.ch>2015-10-29 15:58:05 +0100
commit55274adedcabdc3f1e4d66b2c3b77b1612acf20d (patch)
tree0d6b5cd7315022b5dd543698a9dcdd51eb050fda
parentdbd83f04dfb4b4265a290bad6a1813825f7ab3c6 (diff)
ring: Simplify calculation of number of frames in a tpacket ring
The number of frames in a tpacket ring (ring->layout.tp_frame_nr) is currently calculated as: tp_frame_nr = tp_block_size / tp_frame_size * tp_block_nr Substituting tp_block_nr with 'size / tp_block_size' (as calculated in the line above), we get: tp_frame_nr = tp_block_size / tp_frame_size * (size / tp_block_size) and realize that we can omit tp_block_size as it cancels out, leading to: tp_frame_nr = 1 / tp_frame_size * (size / 1) = size / tp_frame_size Adjust the calculation in setup_ring_layout_generic() accordingly. Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
-rw-r--r--ring.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/ring.c b/ring.c
index 26de18e..dc58a07 100644
--- a/ring.c
+++ b/ring.c
@@ -34,10 +34,7 @@ void setup_ring_layout_generic(int sock, struct ring *ring, size_t size,
TPACKET_ALIGNMENT << 7);
ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
- ring->layout.tp_frame_nr = ring->layout.tp_block_size /
- ring->layout.tp_frame_size *
- ring->layout.tp_block_nr;
-
+ ring->layout.tp_frame_nr = size / ring->layout.tp_frame_size;
}
void mmap_ring_generic(int sock, struct ring *ring)