Messages in this thread Patch in this message | | | From | Arnaldo Carvalho de Melo <> | Subject | [PATCH 14/25] perf map: Use bitmap for booleans | Date | Tue, 19 Nov 2019 08:32:34 -0300 |
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From: Arnaldo Carvalho de Melo <acme@redhat.com>
The map->priv and map->erange_warned are seldom used, the first only in tests/vmlinux-kallsyms.c, the later only when hist_entry__inc_addr_samples() returns -ERANGE in 'perf top', which are really rare occasions, so make them a bool bitfield.
This will open up space for other members on the first cacheline.
$ pahole -C map ~/bin/perf struct map { union { struct rb_node rb_node __attribute__((__aligned__(8))); /* 0 24 */ struct list_head node; /* 0 16 */ } __attribute__((__aligned__(8))); /* 0 24 */ u64 start; /* 24 8 */ u64 end; /* 32 8 */ _Bool erange_warned:1; /* 40: 0 1 */ _Bool priv:1; /* 40: 1 1 */
/* XXX 6 bits hole, try to pack */ /* XXX 3 bytes hole, try to pack */
u32 prot; /* 44 4 */ u32 flags; /* 48 4 */
/* XXX 4 bytes hole, try to pack */
u64 pgoff; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ u64 reloc; /* 64 8 */ u32 maj; /* 72 4 */ u32 min; /* 76 4 */ u64 ino; /* 80 8 */ u64 ino_generation; /* 88 8 */ u64 (*map_ip)(struct map *, u64); /* 96 8 */ u64 (*unmap_ip)(struct map *, u64); /* 104 8 */ struct dso * dso; /* 112 8 */ refcount_t refcnt; /* 120 4 */
/* size: 128, cachelines: 2, members: 17 */ /* sum members: 116, holes: 2, sum holes: 7 */ /* sum bitfield members: 2 bits, bit holes: 1, sum bit holes: 6 bits */ /* padding: 4 */ /* forced alignments: 1 */ } __attribute__((__aligned__(8))); $
Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-g5545pcq4ff0wr17tfb1piqt@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/util/map.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h index a31e80991189..e2466aa5bb41 100644 --- a/tools/perf/util/map.h +++ b/tools/perf/util/map.h @@ -25,8 +25,8 @@ struct map { }; u64 start; u64 end; - bool erange_warned; - u32 priv; + bool erange_warned:1; + bool priv:1; u32 prot; u32 flags; u64 pgoff; -- 2.21.0
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