On Thu, Feb 06, 2025 at 07:26:26PM +0100, Alexander Lobakin wrote: > There are cases when we need to explicitly unroll loops. For example, > cache operations, filling DMA descriptors on very high speeds etc. > Add compiler-specific attribute macros to give the compiler a hint > that we'd like to unroll a loop. > Example usage: > > #define UNROLL_BATCH 8 > > unrolled_count(UNROLL_BATCH) > for (u32 i = 0; i < UNROLL_BATCH; i++) > op(priv, i); > > Note that sometimes the compilers won't unroll loops if they think this > would have worse optimization and perf than without unrolling, and that > unroll attributes are available only starting GCC 8. For older compiler > versions, no hints/attributes will be applied. > For better unrolling/parallelization, don't have any variables that > interfere between iterations except for the iterator itself. > > Co-developed-by: Jose E. Marchesi <jose.marchesi@xxxxxxxxxx> # pragmas > Signed-off-by: Jose E. Marchesi <jose.marchesi@xxxxxxxxxx> > Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@xxxxxxxxx> > Signed-off-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx> Hi Alexander, This patch adds four variants of the unrolled helper. But as far as I can tell the patch-set only makes use of one of them, unrolled_count(). I think it would be best if this patch only added helpers that are used. ...
