| Message ID | 20231013121355.2125824-1-visitorckw@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/i915/gvt: Optimize mmio_offset_compare() for efficiency | expand |
diff --git a/drivers/gpu/drm/i915/gvt/debugfs.c b/drivers/gpu/drm/i915/gvt/debugfs.c index baccbf1761b7..d85d8a3b5ae5 100644 --- a/drivers/gpu/drm/i915/gvt/debugfs.c +++ b/drivers/gpu/drm/i915/gvt/debugfs.c @@ -48,11 +48,7 @@ static int mmio_offset_compare(void *priv, ma = container_of(a, struct diff_mmio, node); mb = container_of(b, struct diff_mmio, node); - if (ma->offset < mb->offset) - return -1; - else if (ma->offset > mb->offset) - return 1; - return 0; + return (int)ma->offset - (int)mb->offset; } static inline int mmio_diff_handler(struct intel_gvt *gvt,
The original code used conditional branching in the mmio_offset_compare function to compare two values and return -1, 1, or 0 based on the result. However, the list_sort comparison function only needs results <0, >0, or =0. This patch optimizes the code to make the comparison branchless, improving efficiency and reducing code size. This change reduces the number of comparison operations from 1-2 to a single subtraction operation, thereby saving the number of instructions. Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> --- v1 -> v2: - Add explicit type cast in case the sizes of u32 and int differ. drivers/gpu/drm/i915/gvt/debugfs.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)