Searched hist:"12 b316d4" (Results 1 – 2 of 2) sorted by relevance
/openbmc/qemu/ui/ |
H A D | vnc.h | 12b316d4 Wed Jan 08 03:08:35 CST 2014 Peter Lieven <pl@kamp.de> ui/vnc: optimize dirty bitmap tracking vnc_update_client currently scans the dirty bitmap of each client bitwise which is a very costly operation if only few bits are dirty. vnc_refresh_server_surface does almost the same. this patch optimizes both by utilizing the heavily optimized function find_next_bit to find the offset of the next dirty bit in the dirty bitmaps. The following artifical test (just the bitmap operation part) running vnc_update_client 65536 times on a 2560x2048 surface illustrates the performance difference: All bits clean - vnc_update_client_new: 0.07 secs vnc_update_client_old: 10.98 secs All bits dirty - vnc_update_client_new: 11.26 secs vnc_update_client_old: 20.19 secs Few bits dirty - vnc_update_client_new: 0.08 secs vnc_update_client_old: 10.98 secs The case for all bits dirty is still rather slow, this is due to the implementation of find_and_clear_dirty_height. This will be addresses in a separate patch. Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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H A D | vnc.c | 12b316d4 Wed Jan 08 03:08:35 CST 2014 Peter Lieven <pl@kamp.de> ui/vnc: optimize dirty bitmap tracking vnc_update_client currently scans the dirty bitmap of each client bitwise which is a very costly operation if only few bits are dirty. vnc_refresh_server_surface does almost the same. this patch optimizes both by utilizing the heavily optimized function find_next_bit to find the offset of the next dirty bit in the dirty bitmaps. The following artifical test (just the bitmap operation part) running vnc_update_client 65536 times on a 2560x2048 surface illustrates the performance difference: All bits clean - vnc_update_client_new: 0.07 secs vnc_update_client_old: 10.98 secs All bits dirty - vnc_update_client_new: 11.26 secs vnc_update_client_old: 20.19 secs Few bits dirty - vnc_update_client_new: 0.08 secs vnc_update_client_old: 10.98 secs The case for all bits dirty is still rather slow, this is due to the implementation of find_and_clear_dirty_height. This will be addresses in a separate patch. Signed-off-by: Peter Lieven <pl@kamp.de> Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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