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Date: Mon, 14 May 2012 21:28:07 -0600 From: David Ahern <dsahern@...il.com> To: Arnaldo Carvalho de Melo <acme@...stprotocols.net>, Namhyung Kim <namhyung.kim@....com> CC: linux-kernel@...r.kernel.org Subject: Re: [PATCH] perf-record: Create events initially disabled -- again On 5/14/12 7:52 PM, David Ahern wrote: > On 5/14/12 8:54 AM, Arnaldo Carvalho de Melo wrote: >> Em Mon, May 14, 2012 at 08:21:02AM -0600, David Ahern escreveu: >>> On 5/14/12 7:09 AM, David Ahern wrote: >>>>> A problem I see is that it'll break group handling again: >>>>> >>>>> $ ./perf stat -g sleep 1 >>>>> >>>>> Performance counter stats for 'sleep 1': >>>>> >>>>> <not counted> task-clock >>>>> <not counted> context-switches >>>>> <not counted> CPU-migrations >>>>> <not counted> page-faults >>>>> <not counted> cycles >>>>> <not counted> stalled-cycles-frontend >>>>> <not counted> stalled-cycles-backend >>>>> <not counted> instructions >>>>> <not counted> branches >>>>> <not counted> branch-misses >>>>> >>>>> 1.000868932 seconds time elapsed >>>>> >>>>> So I suggest changing perf_target__none() check to a proper one >>>>> (perf_target__no_cpu? - the name might be changed soon) for your >>>>> purpose. >>>> >>>> Something else is wrong then. I tested that command (saw your patch in >>>> the history) and it worked for me. Also, this code path does not affect >>>> perf-stat -- it touches perf-record and perf-test only. >>> >>> I think it is something else. I am running latest git tree >>> (3.4.0-rc7). perf from Linus' tree and acme/core both show: >>> >>> perf stat -g -- find /usr>/dev/null >>> >>> Performance counter stats for 'find /usr': >>> >>> <not counted> task-clock >>> <not counted> context-switches >>> <not counted> CPU-migrations >>> <not counted> page-faults >>> <not counted> cycles >>> <not counted> stalled-cycles-frontend >>> <not counted> stalled-cycles-backend >>> <not counted> instructions >>> <not counted> branches >>> <not counted> branch-misses >>> >>> 0.111976940 seconds time elapsed >>> >>> (Using find to make sure some work is done as opposed to sleep; >>> openssl speed also shows the above.) >> >> [acme@...dy ~]$ perf stat -g -- find /usr>/dev/null >> find: `/usr/lib64/audit': Permission denied >> ^Cfind: Interrupt >> >> Performance counter stats for 'find /usr': >> >> <not counted> task-clock >> <not counted> context-switches >> <not counted> CPU-migrations >> <not counted> page-faults >> <not counted> cycles >> <not counted> stalled-cycles-frontend >> <not counted> stalled-cycles-backend >> <not counted> instructions >> <not counted> branches >> <not counted> branch-misses >> >> 1.282060271 seconds time elapsed >> >> >> [acme@...dy ~]$ uname -r >> 3.4.0-rc4-uprobes+ >> >> But: >> >> [acme@...icio linux]$ uname -r >> 3.4.0-rc3+ >> [acme@...icio linux]$ perf stat -g -- find /usr>/dev/null >> ^Cfind: Interrupt >> >> Performance counter stats for 'find /usr': >> >> 126.499751 task-clock # 0.122 CPUs utilized >> <not counted> context-switches >> <not counted> CPU-migrations >> <not counted> page-faults >> 366,694,182 cycles # 2.899 GHz >> 151,332,137 stalled-cycles-frontend # 41.27% frontend cycles idle >> 103,373,418 stalled-cycles-backend # 28.19% backend cycles idle >> 408,309,250 instructions # 1.11 insns per cycle >> # 0.37 stalled cycles >> # per insn >> 77,453,802 branches # 612.284 M/sec >> 1,703,728 branch-misses # 2.20% of all branches >> >> 1.032917277 seconds time elapsed >> >> >> [acme@...icio linux]$ >> >> Bisecting... >> >> - Arnaldo > > Seems like a few issues going on here. In all case the command run is: > perf stat -g -- find / >/dev/null > > v3.1 kernel, v3.1 perf command -- command runs fine and generates output. > > v3.2 kernel, v3.2 perf command -- fails - no output and nothing in dmesg. > > Using latest acme/core version of perf generates a WARNING on all > versions tried - v3.1, v3.2, v3.4-rc3, and v3.4-rc7: > > [ 143.964857] ------------[ cut here ]------------ > [ 143.964870] WARNING: at > /mnt/sw/kernels/kernel-2.6.git/arch/x86/kernel/cpu/perf_event.c:860 > x86_pmu_start+0xdc/0x110() > [ 143.964873] Hardware name: Bochs > [ 143.964875] Modules linked in: lockd ip6t_REJECT nf_conntrack_ipv6 > nf_conntrack_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 xt_state nf_conntrack > ip6table_filter ip6_tables ppdev parport_pc parport virtio_net i2c_piix4 > i2c_core sunrpc virtio_blk [last unloaded: scsi_wait_scan] > [ 143.964897] Pid: 968, comm: find Not tainted 3.2.0 #1 > [ 143.964900] Call Trace: > [ 143.964908] [<ffffffff8106dd2f>] warn_slowpath_common+0x7f/0xc0 > [ 143.964913] [<ffffffff8106dd8a>] warn_slowpath_null+0x1a/0x20 > [ 143.964917] [<ffffffff810248bc>] x86_pmu_start+0xdc/0x110 > [ 143.964921] [<ffffffff81024f32>] x86_pmu_enable+0x212/0x270 > [ 143.964928] [<ffffffff8110f946>] perf_event_context_sched_in+0xe6/0x100 > [ 143.964932] [<ffffffff8111131e>] perf_event_comm+0x11e/0x330 > [ 143.964940] [<ffffffff81378284>] ? get_random_int+0x74/0x90 > [ 143.964947] [<ffffffff8117be40>] set_task_comm+0x60/0x70 > [ 143.964951] [<ffffffff8117c541>] setup_new_exec+0xe1/0x2d0 > [ 143.964958] [<ffffffff811c47ec>] load_elf_binary+0x3ec/0x1a10 > [ 143.964972] [<ffffffff8113c672>] ? get_user_pages+0x52/0x60 > [ 143.964977] [<ffffffff8117a168>] ? get_user_arg_ptr+0x38/0x80 > [ 143.964982] [<ffffffff8117af2c>] search_binary_handler+0xec/0x300 > [ 143.964986] [<ffffffff811c4400>] ? do_mmap+0x40/0x40 > [ 143.964990] [<ffffffff8117c2eb>] do_execve_common+0x2ab/0x330 > [ 143.964994] [<ffffffff8117c3aa>] do_execve+0x3a/0x40 > [ 143.964998] [<ffffffff8101d347>] sys_execve+0x47/0x70 > [ 143.965010] [<ffffffff815d9bdc>] stub_execve+0x6c/0xc0 > [ 143.965013] ---[ end trace 8de43f6b89ac81e1 ]--- I think I'm getting dizzy, and I knew I tested the whole 'perf-stat -g' thing. It works *fine* on a Westmere box (E5620); the above comments apply to a VM on a Nehalem server (E5540). (host is running 3.4.0-rc7 kernel and -cpu host argument for qemu-kvm.) Namhyung/Arnaldo: What processor are you using? David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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