Add block histogram to zdb

The block histogram tracks the changes to psize, lsize and asize
both in the count of the number of blocks (by blocksize) and the
total length of all of the blocks for that blocksize.  It also
keeps a running total of the cumulative size of all of the blocks
up to each size to help determine the size of caching SSDs to be
added to zfs hardware deployments.

The block history counts and lengths are summarized in bins
which are powers of two. Even rows with counts of zero are printed.

This change is accessed by specifying one of two options:

zdb -bbb pool
zdb -Pbbb pool

The first version prints the table in fixed size columns.
The second prints in "parseable" output that can be placed into
a CSV file.

Fixed Column, nicenum output sample:
  block   psize                lsize                asize
   size   Count Length   Cum.  Count Length   Cum.  Count Length   Cum.
    512:  3.50K  1.75M  1.75M  3.43K  1.71M  1.71M  3.41K  1.71M  1.71M
     1K:  3.65K  3.67M  5.43M  3.43K  3.44M  5.15M  3.50K  3.51M  5.22M
     2K:  3.45K  6.92M  12.3M  3.41K  6.83M  12.0M  3.59K  7.26M  12.5M
     4K:  3.44K  13.8M  26.1M  3.43K  13.7M  25.7M  3.49K  14.1M  26.6M
     8K:  3.42K  27.3M  53.5M  3.41K  27.3M  53.0M  3.44K  27.6M  54.2M
    16K:  3.43K  54.9M   108M  3.50K  56.1M   109M  3.42K  54.7M   109M
    32K:  3.44K   110M   219M  3.41K   109M   218M  3.43K   110M   219M
    64K:  3.41K   218M   437M  3.41K   218M   437M  3.44K   221M   439M
   128K:  3.41K   437M   874M  3.70K   474M   911M  3.41K   437M   876M
   256K:  3.41K   874M  1.71G  3.41K   874M  1.74G  3.41K   874M  1.71G
   512K:  3.41K  1.71G  3.41G  3.41K  1.71G  3.45G  3.41K  1.71G  3.42G
     1M:  3.41K  3.41G  6.82G  3.41K  3.41G  6.86G  3.41K  3.41G  6.83G
     2M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
     4M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
     8M:      0      0  6.82G      0      0  6.86G      0      0  6.83G
    16M:      0      0  6.82G      0      0  6.86G      0      0  6.83G

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Robert E. Novak <[email protected]>
Closes: #9158 
Closes #10315 

1 files changed, 203 insertions, 0 deletions

diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index 763a086ac..a329e4a83 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -4161,6 +4161,7 @@ static const char *zdb_ot_extname[] = {
 };
 
 #define	ZB_TOTAL	DN_MAX_LEVELS
+#define	SPA_MAX_FOR_16M	(SPA_MAXBLOCKSHIFT+1)
 
 typedef struct zdb_cb {
 	zdb_blkstats_t	zcb_type[ZB_TOTAL + 1][ZDB_OT_TOTAL + 1];
@@ -4168,6 +4169,15 @@ typedef struct zdb_cb {
 	uint64_t	zcb_checkpoint_size;
 	uint64_t	zcb_dedup_asize;
 	uint64_t	zcb_dedup_blocks;
+	uint64_t	zcb_psize_count[SPA_MAX_FOR_16M];
+	uint64_t	zcb_lsize_count[SPA_MAX_FOR_16M];
+	uint64_t	zcb_asize_count[SPA_MAX_FOR_16M];
+	uint64_t	zcb_psize_len[SPA_MAX_FOR_16M];
+	uint64_t	zcb_lsize_len[SPA_MAX_FOR_16M];
+	uint64_t	zcb_asize_len[SPA_MAX_FOR_16M];
+	uint64_t	zcb_psize_total;
+	uint64_t	zcb_lsize_total;
+	uint64_t	zcb_asize_total;
 	uint64_t	zcb_embedded_blocks[NUM_BP_EMBEDDED_TYPES];
 	uint64_t	zcb_embedded_histogram[NUM_BP_EMBEDDED_TYPES]
 	    [BPE_PAYLOAD_SIZE + 1];
@@ -4191,6 +4201,172 @@ same_metaslab(spa_t *spa, uint64_t vdev, uint64_t off1, uint64_t off2)
 	return ((off1 >> ms_shift) == (off2 >> ms_shift));
 }
 
+/*
+ * Used to simplify reporting of the histogram data.
+ */
+typedef struct one_histo {
+	char *name;
+	uint64_t *count;
+	uint64_t *len;
+	uint64_t cumulative;
+} one_histo_t;
+
+/*
+ * The number of separate histograms processed for psize, lsize and asize.
+ */
+#define	NUM_HISTO 3
+
+/*
+ * This routine will create a fixed column size output of three different
+ * histograms showing by blocksize of 512 - 2^ SPA_MAX_FOR_16M
+ * the count, length and cumulative length of the psize, lsize and
+ * asize blocks.
+ *
+ * All three types of blocks are listed on a single line
+ *
+ * By default the table is printed in nicenumber format (e.g. 123K) but
+ * if the '-P' parameter is specified then the full raw number (parseable)
+ * is printed out.
+ */
+static void
+dump_size_histograms(zdb_cb_t *zcb)
+{
+	/*
+	 * A temporary buffer that allows us to convert a number into
+	 * a string using zdb_nicenumber to allow either raw or human
+	 * readable numbers to be output.
+	 */
+	char numbuf[32];
+
+	/*
+	 * Define titles which are used in the headers of the tables
+	 * printed by this routine.
+	 */
+	const char blocksize_title1[] = "block";
+	const char blocksize_title2[] = "size";
+	const char count_title[] = "Count";
+	const char length_title[] = "Size";
+	const char cumulative_title[] = "Cum.";
+
+	/*
+	 * Setup the histogram arrays (psize, lsize, and asize).
+	 */
+	one_histo_t parm_histo[NUM_HISTO];
+
+	parm_histo[0].name = "psize";
+	parm_histo[0].count = zcb->zcb_psize_count;
+	parm_histo[0].len = zcb->zcb_psize_len;
+	parm_histo[0].cumulative = 0;
+
+	parm_histo[1].name = "lsize";
+	parm_histo[1].count = zcb->zcb_lsize_count;
+	parm_histo[1].len = zcb->zcb_lsize_len;
+	parm_histo[1].cumulative = 0;
+
+	parm_histo[2].name = "asize";
+	parm_histo[2].count = zcb->zcb_asize_count;
+	parm_histo[2].len = zcb->zcb_asize_len;
+	parm_histo[2].cumulative = 0;
+
+
+	(void) printf("\nBlock Size Histogram\n");
+	/*
+	 * Print the first line titles
+	 */
+	if (dump_opt['P'])
+		(void) printf("\n%s\t", blocksize_title1);
+	else
+		(void) printf("\n%7s   ", blocksize_title1);
+
+	for (int j = 0; j < NUM_HISTO; j++) {
+		if (dump_opt['P']) {
+			if (j < NUM_HISTO - 1) {
+				(void) printf("%s\t\t\t", parm_histo[j].name);
+			} else {
+				/* Don't print trailing spaces */
+				(void) printf("  %s", parm_histo[j].name);
+			}
+		} else {
+			if (j < NUM_HISTO - 1) {
+				/* Left aligned strings in the output */
+				(void) printf("%-7s              ",
+				    parm_histo[j].name);
+			} else {
+				/* Don't print trailing spaces */
+				(void) printf("%s", parm_histo[j].name);
+			}
+		}
+	}
+	(void) printf("\n");
+
+	/*
+	 * Print the second line titles
+	 */
+	if (dump_opt['P']) {
+		(void) printf("%s\t", blocksize_title2);
+	} else {
+		(void) printf("%7s ", blocksize_title2);
+	}
+
+	for (int i = 0; i < NUM_HISTO; i++) {
+		if (dump_opt['P']) {
+			(void) printf("%s\t%s\t%s\t",
+			    count_title, length_title, cumulative_title);
+		} else {
+			(void) printf("%7s%7s%7s",
+			    count_title, length_title, cumulative_title);
+		}
+	}
+	(void) printf("\n");
+
+	/*
+	 * Print the rows
+	 */
+	for (int i = SPA_MINBLOCKSHIFT; i < SPA_MAX_FOR_16M; i++) {
+
+		/*
+		 * Print the first column showing the blocksize
+		 */
+		zdb_nicenum((1ULL << i), numbuf, sizeof (numbuf));
+
+		if (dump_opt['P']) {
+			printf("%s", numbuf);
+		} else {
+			printf("%7s:", numbuf);
+		}
+
+		/*
+		 * Print the remaining set of 3 columns per size:
+		 * for psize, lsize and asize
+		 */
+		for (int j = 0; j < NUM_HISTO; j++) {
+			parm_histo[j].cumulative += parm_histo[j].len[i];
+
+			zdb_nicenum(parm_histo[j].count[i],
+			    numbuf, sizeof (numbuf));
+			if (dump_opt['P'])
+				(void) printf("\t%s", numbuf);
+			else
+				(void) printf("%7s", numbuf);
+
+			zdb_nicenum(parm_histo[j].len[i],
+			    numbuf, sizeof (numbuf));
+			if (dump_opt['P'])
+				(void) printf("\t%s", numbuf);
+			else
+				(void) printf("%7s", numbuf);
+
+			zdb_nicenum(parm_histo[j].cumulative,
+			    numbuf, sizeof (numbuf));
+			if (dump_opt['P'])
+				(void) printf("\t%s", numbuf);
+			else
+				(void) printf("%7s", numbuf);
+		}
+		(void) printf("\n");
+	}
+}
+
 static void
 zdb_count_block(zdb_cb_t *zcb, zilog_t *zilog, const blkptr_t *bp,
     dmu_object_type_t type)
@@ -4284,6 +4460,28 @@ zdb_count_block(zdb_cb_t *zcb, zilog_t *zilog, const blkptr_t *bp,
 		    [BPE_GET_PSIZE(bp)]++;
 		return;
 	}
+	/*
+	 * The binning histogram bins by powers of two up to
+	 * SPA_MAXBLOCKSIZE rather than creating bins for
+	 * every possible blocksize found in the pool.
+	 */
+	int bin = highbit64(BP_GET_PSIZE(bp)) - 1;
+
+	zcb->zcb_psize_count[bin]++;
+	zcb->zcb_psize_len[bin] += BP_GET_PSIZE(bp);
+	zcb->zcb_psize_total += BP_GET_PSIZE(bp);
+
+	bin = highbit64(BP_GET_LSIZE(bp)) - 1;
+
+	zcb->zcb_lsize_count[bin]++;
+	zcb->zcb_lsize_len[bin] += BP_GET_LSIZE(bp);
+	zcb->zcb_lsize_total += BP_GET_LSIZE(bp);
+
+	bin = highbit64(BP_GET_ASIZE(bp)) - 1;
+
+	zcb->zcb_asize_count[bin]++;
+	zcb->zcb_asize_len[bin] += BP_GET_ASIZE(bp);
+	zcb->zcb_asize_total += BP_GET_ASIZE(bp);
 
 	if (dump_opt['L'])
 		return;
@@ -5645,6 +5843,11 @@ dump_block_stats(spa_t *spa)
 				}
 			}
 		}
+
+		/* Output a table summarizing block sizes in the pool */
+		if (dump_opt['b'] >= 2) {
+			dump_size_histograms(&zcb);
+		}
 	}
 
 	(void) printf("\n");