[lttng-dev] Odd behaviour of lttng 2.0 kernel event listing
David Goulet
dgoulet at efficios.com
Mon Jan 23 13:24:06 EST 2012
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Hi Daniel,
You have the exact same output as mine.
51 events is correct and the return data size is 41224. We'll have to add debug
output. Let's check the event name returned by the kernel and those we send
back. Please add this to the git head of lttng-tools:
diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index 3b0d6e5..74dc457 100644
- --- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -593,6 +593,8 @@ ssize_t kernel_list_events(int tracer_fd, struct lttng_event
**events)
strncpy(elist[count].name, event, LTTNG_SYMBOL_NAME_LEN);
elist[count].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
elist[count].enabled = -1;
+ DBG3("Kernel event received '%s' and '%s' added to list", event,
+ elist[count].name);
count++;
}
Send back the results and from there we'll see if the event names returned by
lttng-modules are correct.
Thanks!
David
On 12-01-20 04:30 PM, Thibault, Daniel wrote:
>> This is very odd...
>>
>> The "DEBUG1: SIGCHLD catched [in sighandler() at lttng.c:179]" shows you that
>> when this signal is caught by the lttng client, it means that the session daemon
>> is ready hence the lttng modules are loaded for sure. The session daemon send
>> this signal only when it's ready to receive commands.
>>
>> I think I have a 2.6.38 kernel hanging around somewhere. I'll try to reproduce
>> this problem.
>>
>> In the meantime, change the lttng client to exec the session daemon in verbose mode:
>> diff --git a/src/bin/lttng/lttng.c b/src/bin/lttng/lttng.c
>> [...]
>> - execlp(pathname, "lttng-sessiond", "--sig-parent", "--quiet", NULL);
>> + execlp(pathname, "lttng-sessiond", "--sig-parent", "-vvv", NULL);
>> [...]
>> And send us the session daemon debug output.
>
> $ sudo lttng -v list -k
> Spawning a session daemon
> DEBUG3: Creating LTTng run directory: /var/run/lttng [in create_lttng_rundir() at main.c:4087]
> DEBUG2: Kernel consumer err path: /var/run/lttng/kconsumerd/error [in main() at main.c:4312]
> DEBUG2: Kernel consumer cmd path: /var/run/lttng/kconsumerd/command [in main() at main.c:4314]
> DEBUG1: Client socket path /var/run/lttng/client-lttng-sessiond [in main() at main.c:4357]
> DEBUG1: Application socket path /var/run/lttng/apps-lttng-sessiond [in main() at main.c:4358]
> DEBUG1: LTTng run directory path: /var/run/lttng [in main() at main.c:4359]
> DEBUG2: UST consumer 32 bits err path: /var/run/lttng/ustconsumerd32/error [in main() at main.c:4368]
> DEBUG2: UST consumer 32 bits cmd path: /var/run/lttng/ustconsumerd32/command [in main() at main.c:4370]
> DEBUG2: UST consumer 64 bits err path: /var/run/lttng/ustconsumerd64/error [in main() at main.c:4379]
> DEBUG2: UST consumer 64 bits cmd path: /var/run/lttng/ustconsumerd64/command [in main() at main.c:4381]
> DEBUG2: Creating consumer directory: /var/run/lttng/kconsumerd [in set_consumer_sockets() at main.c:4129]
> DEBUG1: Got debugfs path : /sys/kernel/debug [in init_kernel_tracer() at main.c:1790]
> DEBUG1: Modprobe successfully lttng-ftrace [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully lttng-kprobes [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully lttng-kretprobes [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully lib-ring-buffer [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully ltt-relay [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully ltt-ring-buffer-client-discard [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully ltt-ring-buffer-client-overwrite [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully ltt-ring-buffer-metadata-client [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully ltt-ring-buffer-client-mmap-discard [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully ltt-ring-buffer-client-mmap-overwrite [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully ltt-ring-buffer-metadata-mmap-client [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully lttng-probe-lttng [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully lttng-types [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully lttng-probe-block [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully lttng-probe-irq [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully lttng-probe-kvm [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Modprobe successfully lttng-probe-sched [in modprobe_kernel_modules() at main.c:1732]
> DEBUG1: Kernel tracer fd 6 [in init_kernel_tracer() at main.c:1833]
> DEBUG2: Creating consumer directory: /var/run/lttng/ustconsumerd64 [in set_consumer_sockets() at main.c:4129]
> DEBUG2: Creating consumer directory: /var/run/lttng/ustconsumerd32 [in set_consumer_sockets() at main.c:4129]
> DEBUG1: Signal handler set for SIGTERM, SIGPIPE and SIGINT [in set_signal_handler() at main.c:4220]
> DEBUG1: All permissions are set [in set_permissions() at main.c:4058]
> DEBUG3: Created hashtable size 4 at 0xf8c630 of type 1 [in lttng_ht_new() at hashtable.c:96]
> DEBUG3: Created hashtable size 4 at 0xf8c8f0 of type 1 [in lttng_ht_new() at hashtable.c:96]
> DEBUG1: epoll set max size is 206581 [in compat_epoll_set_max_size() at compat/compat-epoll.c:217]
> DEBUG1: Thread manage kernel started [in thread_manage_kernel() at main.c:828]
> DEBUG1: Updating kernel poll set [in update_kernel_poll() at main.c:706]
> DEBUG1: Thread kernel polling on 2 fds [in thread_manage_kernel() at main.c:857]
> DEBUG1: [thread] Manage application started [in thread_manage_apps() at main.c:1085]
> DEBUG1: Apps thread polling on 2 fds [in thread_manage_apps() at main.c:1106]
> DEBUG1: [thread] Manage application registration started [in thread_registration_apps() at main.c:1286]
> DEBUG1: Notifying applications of session daemon state: 1 [in notify_ust_apps() at main.c:645]
> DEBUG1: Got the wait shm fd 18 [in get_wait_shm() at shm.c:113]
> DEBUG1: Futex wait update active 1 [in futex_wait_update() at futex.c:63]
> DEBUG1: Accepting application registration [in thread_registration_apps() at main.c:1317]
> DEBUG1: [thread] Dispatch UST command started [in thread_dispatch_ust_registration() at main.c:1218]
> DEBUG1: Futex n to 1 prepare done [in futex_nto1_prepare() at futex.c:74]
> DEBUG1: Woken up but nothing in the UST command queue [in thread_dispatch_ust_registration() at main.c:1228]
> DEBUG1: [thread] Manage client started [in thread_manage_clients() at main.c:3629]
> DEBUG1: SIGCHLD catched [in sighandler() at lttng.c:179]
> DEBUG1: Getting kernel tracing events [in list_kernel_events() at commands/list.c:277]
> DEBUG1: Accepting client command ... [in thread_manage_clients() at main.c:3661]
> DEBUG1: Wait for client response [in thread_manage_clients() at main.c:3691]
> DEBUG1: Receiving data from client ... [in thread_manage_clients() at main.c:3726]
> DEBUG1: Processing client command 14 [in process_client_msg() at main.c:3212]
> DEBUG1: Kernel list events done (51 events) [in kernel_list_events() at kernel.c:600]
> DEBUG1: Sending response (size: 41224, retcode: Success) [in thread_manage_clients() at main.c:3760]
> Kernel events:
> -------------
> sched_kthread_stop (type: tracepoint)
> [...]
> kvm_msi_set_irq (type: tracepoint)
> (type: tracepoint) [disabled]
> [...]
> (type: tracepoint) [disabled]
>
> DEBUG1: Clean command context structure [in clean_command_ctx() at main.c:492]
> DEBUG1: Accepting client command ... [in thread_manage_clients() at main.c:3661]
>
> Daniel U. Thibault
> R & D pour la défense Canada - Valcartier (RDDC Valcartier) / Defence R&D Canada - Valcartier (DRDC Valcartier)
> Système de systèmes (SdS) / System of Systems (SoS)
> Solutions informatiques et expérimentations (SIE) / Computing Solutions and Experimentations (CSE)
> 2459 Boul. Pie XI Nord
> Québec, QC G3J 1X5
> CANADA
> Vox : (418) 844-4000 x4245
> Fax : (418) 844-4538
> NAC: 918V QSDJ
> Gouvernement du Canada / Government of Canada
> <http://www.valcartier.drdc-rddc.gc.ca/>
>
> _______________________________________________
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>
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