Update CHANGELOG

CHANGELOG.md

@@ -4,29 +4,57 @@ CHANGELOG
 0.9.4
 -----
 
-#### New features
+### New features
 
-- Added `--tac` option to reverse the order of the input.
+#### Added `--tac` option to reverse the order of the input.
-    - One might argue that this option is unnecessary since we can already put
-      `tac` or `tail -r` in the command pipeline to achieve the same result.
-      However, the advantage of `--tac` is that it does not block until the
-      input is complete.
 
-#### *Backward incompatible changes*
+One might argue that this option is unnecessary since we can already put `tac`
+or `tail -r` in the command pipeline to achieve the same result. However, the
+advantage of `--tac` is that it does not block until the input is complete.
+
+### *Backward incompatible changes*
+
+#### Changed behavior on `--no-sort`
+
+`--no-sort` option will no longer reverse the display order within finder. You
+may want to use the new `--tac` option with `--no-sort`.
 
-- `--no-sort` option will no longer reverse the display order. You may want to
-  use the new `--tac` option with `--no-sort`.
 ```
 history | fzf +s --tac
 ```
 
+### Improvements
+
+#### `--filter` will not block when sort is disabled
+
+When fzf works in filtering mode (`--filter`) and sort is disabled
+(`--no-sort`), there's no need to block until input is complete. The new
+version of fzf will print the matches on-the-fly when the following condition
+is met:
+
+    --filter TERM --no-sort [--no-tac --no-sync]
+
+or simply:
+
+    -f TERM +s
+
+This change removes unnecessary delay in the use cases like the following:
+
+    fzf -f xxx +s | head -5
+
+However, in this case, fzf processes the lines sequentially, so it cannot
+utilize multiple cores, and fzf will run slightly slower than the previous
+mode of execution where filtering is done in parallel after the entire input
+is loaded. If the user is concerned about this performance problem, one can
+add `--sync` option to re-enable buffering.
+
 0.9.3
 -----
 
-#### New features
+### New features
 - Added `--sync` option for multi-staged filtering
 
-#### Improvements
+### Improvements
 - `--select-1` and `--exit-0` will start finder immediately when the condition
   cannot be met