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authorNamhyung Kim <namhyung@kernel.org>2025-04-01 09:30:55 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2025-04-29 18:23:53 +0300
commit13f35928a4e6fe158f358c3d2f16c2319f1ace53 (patch)
tree245ae7e6b50fd31b15521b2bd6d4a3927638bdee /tools/perf/scripts/python/export-to-sqlite.py
parent2d099ccaadf623d3aaa7f8b60dbd9eb3f5b375ac (diff)
downloadlinux-13f35928a4e6fe158f358c3d2f16c2319f1ace53.tar.xz
perf lock contention: Symbolize zone->lock using BTF
The struct zone is embedded in struct pglist_data which can be allocated for each NUMA node early in the boot process. As it's not a slab object nor a global lock, this was not symbolized. Since the zone->lock is often contended, it'd be nice if we can symbolize it. On NUMA systems, node_data array will have pointers for struct pglist_data. By following the pointer, it can calculate the address of each zone and its lock using BTF. On UMA, it can just use contig_page_data and its zones. The following example shows the zone lock contention at the end. $ sudo ./perf lock con -abl -E 5 -- ./perf bench sched messaging # Running 'sched/messaging' benchmark: # 20 sender and receiver processes per group # 10 groups == 400 processes run Total time: 0.038 [sec] contended total wait max wait avg wait address symbol 5167 18.17 ms 10.27 us 3.52 us ffff953340052d00 &kmem_cache_node (spinlock) 38 11.75 ms 465.49 us 309.13 us ffff95334060c480 &sock_inode_cache (spinlock) 3916 10.13 ms 10.43 us 2.59 us ffff953342aecb40 &kmem_cache_node (spinlock) 2963 10.02 ms 13.75 us 3.38 us ffff9533d2344098 &kmalloc-rnd-08-2k (spinlock) 216 5.05 ms 99.49 us 23.39 us ffff9542bf7d65d0 zone_lock (spinlock) Signed-off-by: Namhyung Kim <namhyung@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Song Liu <song@kernel.org> Cc: Stephane Eranian <eranian@google.com> Cc: bpf@vger.kernel.org Cc: linux-mm@kvack.org Link: https://lore.kernel.org/r/20250401063055.7431-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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