perf header: Pack 'struct perf_session_env' ...
Initial struct:
[acme@ssdandy linux]$ pahole -C perf_session_env ~/bin/perf
struct perf_session_env {
char * hostname; /* 0 8 */
char * os_release; /* 8 8 */
char * version; /* 16 8 */
char * arch; /* 24 8 */
int nr_cpus_online; /* 32 4 */
int nr_cpus_avail; /* 36 4 */
char * cpu_desc; /* 40 8 */
char * cpuid; /* 48 8 */
long long unsigned int total_mem; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
int nr_cmdline; /* 64 4 */
/* XXX 4 bytes hole, try to pack */
char * cmdline; /* 72 8 */
int nr_sibling_cores; /* 80 4 */
/* XXX 4 bytes hole, try to pack */
char * sibling_cores; /* 88 8 */
int nr_sibling_threads; /* 96 4 */
/* XXX 4 bytes hole, try to pack */
char * sibling_threads; /* 104 8 */
int nr_numa_nodes; /* 112 4 */
/* XXX 4 bytes hole, try to pack */
char * numa_nodes; /* 120 8 */
/* --- cacheline 2 boundary (128 bytes) --- */
int nr_pmu_mappings; /* 128 4 */
/* XXX 4 bytes hole, try to pack */
char * pmu_mappings; /* 136 8 */
int nr_groups; /* 144 4 */
/* size: 152, cachelines: 3, members: 20 */
/* sum members: 128, holes: 5, sum holes: 20 */
/* padding: 4 */
/* last cacheline: 24 bytes */
};
[acme@ssdandy linux]$
[acme@ssdandy linux]$ pahole -C perf_session_env --reorganize --show_reorg_steps ~/bin/perf | grep ^/ | grep -v Final
/* Moving 'nr_sibling_cores' from after 'cmdline' to after 'nr_cmdline' */
/* Moving 'nr_numa_nodes' from after 'sibling_threads' to after 'nr_sibling_threads' */
/* Moving 'nr_groups' from after 'pmu_mappings' to after 'nr_pmu_mappings' */
[acme@ssdandy linux]$
Final struct stats:
[acme@ssdandy linux]$ pahole -C perf_session_env --reorganize --show_reorg_steps ~/bin/perf | tail -4
/* --- cacheline 2 boundary (128 bytes) --- */
/* size: 128, cachelines: 2, members: 20 */
}; /* saved 24 bytes and 1 cacheline! */
[acme@ssdandy linux]$
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-3d9tshamloinzxcqeb7mtd1n@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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