Messages in this thread | | | Subject | [PROBLEM] perf report is broken in latest linus git | From | Pekka Enberg <> | Date | Thu, 13 Aug 2009 12:28:28 +0300 |
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Hi all!
I don't know what to make out of this. I am profiling my userspace VM with perf and something happened between 2.6.31-rc4 (which worked perfectly) and latest Linus git. I am seeing completely different perf profiles and from what I can tell, the userspace part isn't causing which makes me think it's a kernel bug. See below for the perf reports.
Pekka
Linux 2.6.31-rc4 (both kernel and userspace):
[ Note: this makes the most sense to me knowing what the app does. ]
penberg@penberg-laptop:~/testing/jato$ perf record -f jato HelloWorldSwing [ perf record: Captured and wrote 1.401 MB perf.data (~61218 samples) ] penberg@penberg-laptop:~/testing/jato$ perf report --sort comm,dso,symbol # Samples: 60421 # # Overhead Command Shared Object Symbol # ........ ....... ....................................... ...... # 69.86% jato /home/penberg/bin/jato [.] gc_map_init 2.06% jato /lib/tls/i686/cmov/libc-2.8.90.so [.] _int_malloc 1.95% jato /lib/tls/i686/cmov/libc-2.8.90.so [.] __GI_strcmp 1.68% jato /lib/tls/i686/cmov/libc-2.8.90.so [.] __GI___libc_malloc 1.61% jato [kernel] [k] get_page_from_freelist 1.01% jato /home/penberg/bin/jato [.] zalloc 0.97% jato /usr/lib/libzip.so.1.0.0 [.] _zip_get_name 0.85% jato /home/penberg/bin/jato [.] cafebabe_constant_info_utf8_compare 0.69% jato /usr/lib/libz.so.1.2.3.3 [.] 0x0000000000e445 0.59% jato /lib/tls/i686/cmov/libc-2.8.90.so [.] cfree 0.58% jato /home/penberg/bin/jato [.] analyze_liveness 0.56% jato /home/penberg/bin/jato [.] split_interval_at 0.56% jato /usr/lib/libfontconfig.so.1.3.0 [.] 0x0000000001127e 0.56% jato /home/penberg/bin/jato [.] allocate_registers
Latest Linus git kernel with -rc4 perf userspace:
penberg@penberg-laptop:~/testing/jato$ perf record -f jato HelloWorldSwing [ perf record: Captured and wrote 1.402 MB perf.data (~61261 samples) ]
penberg@penberg-laptop:~/testing/jato$ perf report --sort comm,dso,symbol|head -30 # Samples: 60457 # # Overhead Command Shared Object Symbol # ........ ....... ....................................... ...... #
[ Note: the jato executable doesn't appear anywhere in the trace. I'm pretty sure the libzip functions, for example, are from jato, not perf. ]
36.14% perf /home/penberg/bin/perf [.] dso__synthesize_plt_symbols 35.20% perf /home/penberg/bin/perf [.] dso__new 3.57% perf /home/penberg/bin/jato [.] 0x0000000000c910 2.10% perf /lib/tls/i686/cmov/libc-2.8.90.so [.] _int_malloc 1.89% perf /lib/tls/i686/cmov/libc-2.8.90.so [.] __GI_strcmp 1.63% perf /lib/tls/i686/cmov/libc-2.8.90.so [.] __GI___libc_malloc 1.44% perf [kernel] [k] get_page_from_freelist 1.04% perf /home/penberg/bin/perf [.] dso__load_sym 0.94% perf /usr/lib/libzip.so.1.0.0 [.] _zip_get_name 0.60% perf /lib/tls/i686/cmov/libc-2.8.90.so [.] cfree 0.52% perf /home/penberg/bin/perf [.] dso__load_kernel 0.46% perf /usr/lib/libzip.so.1.0.0 [.] _zip_name_locate 0.46% perf /usr/lib/libfontconfig.so.1.3.0 [.] 0x00000000016706 0.42% perf /lib/tls/i686/cmov/libc-2.8.90.so [.] _int_free 0.40% perf [kernel] [k] kunmap_atomic 0.38% perf /home/penberg/bin/perf [.] cmd_stat 0.34% perf /home/penberg/bin/perf [.] quote_c_style_counted 0.33% perf /usr/lib/libz.so.1.2.3.3 [.] 0x0000000000ea89 0.32% perf /home/penberg/bin/perf [.] 0x000000000261ea 0.32% perf /lib/tls/i686/cmov/libc-2.8.90.so [.] malloc_consolidate 0.30% perf /home/penberg/bin/perf [.] strbuf_grow 0.30% perf /home/penberg/bin/perf [.] store_aux 0.30% perf /home/penberg/bin/jato [.] zalloc 0.29% perf /lib/tls/i686/cmov/libc-2.8.90.so [.] __GI___libc_realloc 0.27% perf /home/penberg/bin/perf [.] strbuf_addf
Latest Linus git kernel and userspace:
[ perf record: Captured and wrote 1.348 MB perf.data (~58887 samples) ] penberg@penberg-laptop:~/testing/jato$ perf record -f jato HelloWorldSwing [ perf record: Captured and wrote 1.342 MB perf.data (~58623 samples) ] penberg@penberg-laptop:~/testing/jato$ perf report | head -30 # Samples: 57821 # # Overhead Command Shared Object Symbol # ........ ....... ....................................... ...... # 72.88% perf /home/penberg/bin/perf [.] strbuf_readlink 6.53% perf /lib/tls/i686/cmov/libc-2.8.90.so [.] 0x0000000014b8c0 3.31% perf /home/penberg/bin/jato [.] 0x0000000000c910 1.37% perf [kernel] [k] get_page_from_freelist 0.91% perf /usr/lib/libzip.so.1.0.0 [.] _zip_get_name 0.67% perf /home/penberg/bin/perf [.] strbuf_getline 0.59% perf /lib/tls/i686/cmov/libc-2.8.90.so [.] __GI_strcmp 0.57% perf /usr/lib/libfontconfig.so.1.3.0 [.] 0x00000000019700 0.53% perf /usr/lib/libz.so.1.2.3.3 [.] 0x0000000000f0c5 0.50% perf /home/penberg/bin/perf [.] print_events 0.48% perf /home/penberg/bin/perf [.] quote_c_style_counted 0.47% perf /home/penberg/bin/perf [.] rb_erase 0.40% perf /home/penberg/bin/perf [.] strlist__load 0.40% perf /home/penberg/bin/perf [.] display_thread 0.40% perf /home/penberg/bin/perf [.] run_hook 0.34% perf [kernel] [k] kunmap_atomic 0.32% perf /home/penberg/bin/perf [.] strlist__parse_list_entry 0.31% perf /lib/tls/i686/cmov/libc-2.8.90.so [.] _int_malloc 0.30% perf /home/penberg/bin/perf [.] dso__load 0.28% perf /usr/lib/libzip.so.1.0.0 [.] _zip_name_locate 0.28% perf /home/penberg/bin/perf [.] cmd_stat 0.26% perf /home/penberg/bin/perf [.] run_command_v_opt 0.25% perf /home/penberg/bin/perf [.] strlist__parse_list 0.23% perf a7d8bb0a [.] 0x000000a7d8bb0a 0.21% perf /home/penberg/bin/jato [.] cafebabe_constant_info_utf8_compare
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