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On 10/26/2025 9:25 AM, Stephen Boyd wrote: > [ EXTERNAL EMAIL ] > > Quoting Chuan Liu via B4 Relay (2025-10-21 03:12:31) >> From: Chuan Liu >> >> There is no need to evaluate further divider values once _is_best_div() >> finds one that matches the target rate. >> >> Signed-off-by: Chuan Liu >> --- >> drivers/clk/clk-divider.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c >> index 2601b6155afb..b92c4f800fa9 100644 >> --- a/drivers/clk/clk-divider.c >> +++ b/drivers/clk/clk-divider.c >> @@ -339,6 +339,9 @@ static int clk_divider_bestdiv(struct clk_hw *hw, struct clk_hw *parent, >> best = now; >> *best_parent_rate = parent_rate; >> } >> + >> + if (best == rate) >> + break; > > This needs a comment. I'm not even sure if it is correct either, because > the other exit from this loop happens if the parent rate can be You're right. Sorry, I was mainly focusing on the number of iterations in the for loop earlier and missed the fact that the parent clock directly participates in the division without changing. > unchanged. I don't think we have any KUnit tests for this file, so > please add some tests that deal with this case explicitly (the parent > rate being unchanged as the desirable part). I'll take some time to get familiar with the principles and methods of KUnit testing, and I'd be happy to help improve it. > > A general comment: these patches have no benefit described in the commit > text. Do you see any performance improvement with this patch? I sorta > doubt this really matters because the number of dividers are typically > small. A single sentence commit text that only says there is no need > doesn't convince me that any work has been put in to research why the > code was written this way or even prove that making this change improves > anything. This patch came about because I noticed that the mux has a similar logic: - Even after finding a suitable clock source, it continues to iterate through and calculate other sources (and even if a later source has the same rate, it won't replace the current one). From there, I went on to examine the divider logic, but I missed the detail that the parent clock doesn't change in the divider. Sorry that this unreasonable patch ended up taking up your time.