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Message-ID: <20120515034649.GA7166@infradead.org> Date: Tue, 15 May 2012 00:46:49 -0300 From: Arnaldo Carvalho de Melo <acme@...stprotocols.net> To: David Ahern <dsahern@...il.com> Cc: Namhyung Kim <namhyung.kim@....com>, linux-kernel@...r.kernel.org Subject: Re: [PATCH] perf-record: Create events initially disabled -- again Em Mon, May 14, 2012 at 09:28:07PM -0600, David Ahern escreveu: > 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? Here it is mostly: [acme@...dy autotest]$ grep "model name" /proc/cpuinfo | sort -u model name : Intel(R) Core(TM) i7-2920XM CPU @ 2.50GHz Sandy Bridge. - Arnaldo -- 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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