Added requested comment and missing comment for UMM_CRITICAL_PERIOD_ANALYZE.

Author: mhightower83

cores/esp8266/umm_malloc/umm_malloc.cpp

@@ -585,7 +585,7 @@ extern int umm_last_fail_alloc_size;
 #if defined(DEBUG_ESP_PORT) || defined(DEBUG_ESP_ISR)
 #define DEBUG_IRAM_ATTR ICACHE_RAM_ATTR
 /*
-   Printing from the malloc routines is tricky. Since a lot of library calls
+  Printing from the malloc routines is tricky. Since a lot of library calls
   will want to do malloc.
 
   Objective:  To be able to print "last gasp" diagnostic messages
@@ -610,6 +610,13 @@ int DEBUG_IRAM_ATTR _isr_safe_printf_P(const char *fmt, ...) {
 #else
   uart_buff_switch(0U); // Side effect, clears RX FIFO
 #endif
+  /*
+    To use ets_strlen() and ets_memcpy() safely with PROGMEM, flash storage,
+    the PROGMEM address must be word (4 bytes) aligned. The destination
+    address for ets_memcpy must also be word-aligned. We also round the
+    buf_len up to the nearest word boundary. So that all transfers will be
+    whole words.
+  */
   size_t str_len = ets_strlen(fmt);
   size_t buf_len = (str_len + 1 + 3) & ~0x03U;
   char ram_buf[buf_len] __attribute__ ((aligned(4)));

cores/esp8266/umm_malloc/umm_malloc_cfg.h

@@ -122,7 +122,16 @@ extern char _heap_start;
 #define DEFAULT_CRITICAL_SECTION_INTLEVEL 15
 #endif
 
-#define UMM_CRITICAL_PERIOD_ANALYZE
+/*
+ * -D UMM_CRITICAL_PERIOD_ANALYZE :
+ *
+ * Build option to collect timing usage data on critical section usage in
+ * functions: info, malloc, realloc. Collects MIN, MAX, and number of time
+ * IRQs were disabled at request time. Note, IRQs disabled value can be
+ * inflated by calls to realloc. realloc may call malloc and/or free.
+ * Examine code for specifics on what info is available and how to access.
+*/
+// #define UMM_CRITICAL_PERIOD_ANALYZE
 
 #ifndef __STRINGIFY
 #define __STRINGIFY(a) #a
@@ -175,7 +184,6 @@ static inline void _critical_entry(time_stat_t *p, uint32_t *saved_ps) {
     *saved_ps = xt_rsil(DEFAULT_CRITICAL_SECTION_INTLEVEL);
     if (0U != (*saved_ps & 0x0FU)) {
         p->intlevel += 1U;
-        // inflight_stack_trace(*saved_ps);
     }
 
     p->start = _umm_get_cycle_count();