diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c index 42b82c08249..46587671202 100644 --- a/cmd/zdb/zdb.c +++ b/cmd/zdb/zdb.c @@ -2152,14 +2152,21 @@ dump_brt(spa_t *spa) if (dump_opt['T'] < 3) return; + /* -TTT shows a per-vdev histograms; -TTTT shows all entries */ + boolean_t do_histo = dump_opt['T'] == 3; + char dva[64]; - printf("\n%-16s %-10s\n", "DVA", "REFCNT"); + + if (!do_histo) + printf("\n%-16s %-10s\n", "DVA", "REFCNT"); for (uint64_t vdevid = 0; vdevid < brt->brt_nvdevs; vdevid++) { brt_vdev_t *brtvd = &brt->brt_vdevs[vdevid]; if (brtvd == NULL || !brtvd->bv_initiated) continue; + uint64_t counts[64] = {}; + zap_cursor_t zc; zap_attribute_t *za = zap_attribute_alloc(); for (zap_cursor_init(&zc, brt->brt_mos, brtvd->bv_mos_entries); @@ -2172,14 +2179,26 @@ dump_brt(spa_t *spa) za->za_integer_length, za->za_num_integers, &refcnt)); - uint64_t offset = *(const uint64_t *)za->za_name; + if (do_histo) + counts[highbit64(refcnt)]++; + else { + uint64_t offset = + *(const uint64_t *)za->za_name; - snprintf(dva, sizeof (dva), "%" PRIu64 ":%llx", vdevid, - (u_longlong_t)offset); - printf("%-16s %-10llu\n", dva, (u_longlong_t)refcnt); + snprintf(dva, sizeof (dva), "%" PRIu64 ":%llx", + vdevid, (u_longlong_t)offset); + printf("%-16s %-10llu\n", dva, + (u_longlong_t)refcnt); + } } zap_cursor_fini(&zc); zap_attribute_free(za); + + if (do_histo) { + printf("\nBRT: vdev %" PRIu64 + ": DVAs with 2^n refcnts:\n", vdevid); + dump_histogram(counts, 64, 0); + } } } diff --git a/man/man8/zdb.8 b/man/man8/zdb.8 index 08f5a3f7004..ae35454ad08 100644 --- a/man/man8/zdb.8 +++ b/man/man8/zdb.8 @@ -14,7 +14,7 @@ .\" Copyright (c) 2017 Lawrence Livermore National Security, LLC. .\" Copyright (c) 2017 Intel Corporation. .\" -.Dd November 18, 2023 +.Dd October 27, 2024 .Dt ZDB 8 .Os . @@ -408,6 +408,8 @@ blocks cloned, the space saving as a result of cloning, and the saving ratio. .It Fl TT Display the per-vdev BRT statistics, including total references. .It Fl TTT +Display histograms of per-vdev BRT refcounts. +.It Fl TTTT Dump the contents of the block reference tables. .It Fl u , -uberblock Display the current uberblock.