_PyMalloc_DebugDumpStats(): vastly improved the output, and it now

accounts for every byte.

diff --git a/Objects/obmalloc.c b/Objects/obmalloc.c
index 7af823b60bf63b596dbfb86dbe831d1f8659a88a..b576123c286d951cdebf6d234e1fc6d5191b87ea 100644 (file)
--- a/Objects/obmalloc.c
+++ b/Objects/obmalloc.c
@@ -252,9 +252,8 @@ typedef struct pool_header *poolp;
 /* Round pointer P down to the closest pool-aligned address <= P, as a poolp */
 #define POOL_ADDR(P) ((poolp)((uptr)(P) & ~(uptr)POOL_SIZE_MASK))
 
-/* Return total number of blocks in poolp P, as a uint. */
-#define NUMBLOCKS(P)   \
-       ((uint)(POOL_SIZE - POOL_OVERHEAD) / INDEX2SIZE((P)->szidx))
+/* Return total number of blocks in pool of size index I, as a uint. */
+#define NUMBLOCKS(I) ((uint)(POOL_SIZE - POOL_OVERHEAD) / INDEX2SIZE(I))
 
 /*==========================================================================*/
 
@@ -1195,24 +1194,48 @@ _PyMalloc_DebugDumpAddress(const void *p)
        }
 }
 
+static ulong
+printone(const char* msg, ulong value)
+{
+       const size_t len = strlen(msg);
+       size_t i;
+
+       fputs(msg, stderr);
+       for (i = len; i < 40; ++i)
+               fputc(' ', stderr);
+       fprintf(stderr, "= %15lu\n", value);
+       return value;
+}
+
 /* Print summary info to stderr about the state of pymalloc's structures. */
 void
 _PyMalloc_DebugDumpStats(void)
 {
        uint i;
        const uint numclasses = SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT;
-       uint numfreepools = 0;
-       /* # of pools per class index */
+       /* # of pools, allocated blocks, and free blocks per class index */
        ulong numpools[SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT];
-       /* # of allocated blocks per class index */
        ulong numblocks[SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT];
-       /* # of free blocks per class index */
        ulong numfreeblocks[SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT];
-       ulong grandtotal;       /* total # of allocated bytes */
-       ulong freegrandtotal;   /* total # of available bytes in used pools */
+       /* total # of allocated bytes in used and full pools */
+       ulong allocated_bytes = 0;
+       /* total # of available bytes in used pools */
+       ulong available_bytes = 0;
+       /* # of free pools + pools not yet carved out of current arena */
+       uint numfreepools = 0;
+       /* # of bytes for arena alignment padding */
+       uint arena_alignment = 0;
+       /* # of bytes in used and full pools used for pool_headers */
+       ulong pool_header_bytes = 0;
+       /* # of bytes in used and full pools wasted due to quantization,
+        * i.e. the necessarily leftover space at the ends of used and
+        * full pools.
+        */
+       ulong quantization = 0;
+       /* running total -- should equal narenas * ARENA_SIZE */
+       ulong total;
+       char buf[128];
 
-       fprintf(stderr, "%u arenas * %d bytes/arena = %lu total bytes.\n",
-               narenas, ARENA_SIZE, narenas * (ulong)ARENA_SIZE);
        fprintf(stderr, "Small block threshold = %d, in %u size classes.\n",
                SMALL_REQUEST_THRESHOLD, numclasses);
        fprintf(stderr, "pymalloc malloc+realloc called %lu times.\n",
@@ -1234,6 +1257,7 @@ _PyMalloc_DebugDumpStats(void)
                poolsinarena = ARENA_SIZE / POOL_SIZE;
                if (base & (uptr)POOL_SIZE_MASK) {
                        --poolsinarena;
+                       arena_alignment += POOL_SIZE;
                        base &= ~(uptr)POOL_SIZE_MASK;
                        base += POOL_SIZE;
                }
@@ -1254,18 +1278,16 @@ _PyMalloc_DebugDumpStats(void)
                        }
                        ++numpools[p->szidx];
                        numblocks[p->szidx] += p->ref.count;
-                       numfreeblocks[p->szidx] += NUMBLOCKS(p) - p->ref.count;
+                       numfreeblocks[p->szidx] += NUMBLOCKS(p->szidx) -
+                                                  p->ref.count;
                }
        }
 
-       fputc('\n', stderr);
-       fprintf(stderr, "Number of unused pools: %u\n", numfreepools);
        fputc('\n', stderr);
        fputs("class   num bytes   num pools   blocks in use  avail blocks\n"
              "-----   ---------   ---------   -------------  ------------\n",
                stderr);
 
-       grandtotal = freegrandtotal = 0;
        for (i = 0; i < numclasses; ++i) {
                ulong p = numpools[i];
                ulong b = numblocks[i];
@@ -1277,14 +1299,29 @@ _PyMalloc_DebugDumpStats(void)
                }
                fprintf(stderr, "%5u %11u %11lu %15lu %13lu\n",
                        i, size, p, b, f);
-               grandtotal += b * size;
-               freegrandtotal += f * size;
+               allocated_bytes += b * size;
+               available_bytes += f * size;
+               pool_header_bytes += p * POOL_OVERHEAD;
+               quantization += p * ((POOL_SIZE - POOL_OVERHEAD) % size);
        }
        fputc('\n', stderr);
-       fprintf(stderr, "Total bytes in allocated blocks: %lu\n",
-               grandtotal);
-       fprintf(stderr, "Total free bytes in used pools:  %lu\n",
-               freegrandtotal);
+
+       PyOS_snprintf(buf, sizeof(buf),
+               "%u arenas * %d bytes/arena", narenas, ARENA_SIZE);
+       (void)printone(buf, (ulong)narenas * ARENA_SIZE);
+
+       fputc('\n', stderr);
+
+       PyOS_snprintf(buf, sizeof(buf),
+               "%u unused pools * %d bytes", numfreepools, POOL_SIZE);
+       total  = printone(buf, (ulong)numfreepools * POOL_SIZE);
+
+       total += printone("# bytes in allocated blocks", allocated_bytes);
+       total += printone("# bytes in available blocks", available_bytes);
+       total += printone("# bytes lost to pool headers", pool_header_bytes);
+       total += printone("# bytes lost to quantization", quantization);
+       total += printone("# bytes lost to arena alignment", arena_alignment);
+       (void)printone("Total", total);
 }
 
 #endif /* PYMALLOC_DEBUG */