add power schedule info

docs/FAQ.md

@@ -180,6 +180,27 @@ If you find an interesting or important question missing, submit it via
   [best_practices.md#improving-stability](best_practices.md#improving-stability).
 </p></details>
 
+<details>
+  <summary id="what-are-power-schedules">What are power schedules?</summary><p>
+
+  Not every item in our queue/corpus is the same, some are more interesting,
+  others provide little value.
+  A power schedule measures how "interesting" a value is, and depending on
+  the calculated value spends more or less time mutating it.
+
+  AFL++ comes with several power schedules, initially ported from [AFLFast](https://github.com/mboehme/aflfast)
+  however modified to be more effective and several more modes added.
+
+  The most effective modes are '-p fast` (default) and `-p explore`.
+
+  If you fuzz with several parallel afl-fuzz instances, then it is beneficial
+  to assign a different schedule to each instance, however the majority should
+  be `fast` and `explore`.
+
+  It does not make sense to explain the details of the calculation and
+  reasoning behind all of the schedules. If you are interested, read the source
+  code and the AFLFast paper.
+
 ## Troubleshooting
 
 <details>

docs/fuzzing_in_depth.md

@@ -562,7 +562,8 @@ All other secondaries should be used like this:
 * a quarter to a third with the MOpt mutator enabled: `-L 0`
 * run with a different power schedule, recommended are:
   `fast (default), explore, coe, lin, quad, exploit and rare` which you can set
-  with, e.g., `-p explore`
+  with the `-p` option, e.g., `-p explore`. See the [FAQ](FAQ.md#what-are-power-schedules)
+  for details.
 * a few instances should use the old queue cycling with `-Z`
 
 Also, it is recommended to set `export AFL_IMPORT_FIRST=1` to load test cases

src/afl-fuzz.c

@@ -105,7 +105,7 @@ static void usage(u8 *argv0, int more_help) {
       "  -p schedule   - power schedules compute a seed's performance score:\n"
       "                  fast(default), explore, exploit, seek, rare, mmopt, "
       "coe, lin\n"
-      "                  quad -- see docs/power_schedules.md\n"
+      "                  quad -- see docs/FAQ.md for more information\n"
       "  -f file       - location read by the fuzzed program (default: stdin "
       "or @@)\n"
       "  -t msec       - timeout for each run (auto-scaled, default %u ms). "