[ltt-dev] Tracing syscall_entry not working

Thu Oct 6 13:04:43 EDT 2011

No I was not grep'ing. I was looking through the vi editor. I do see two metadata entries for the syscall_entry, but no instances of the actual occurrence of those events.

Trace set contains 1 traces

metadata.core_marker_id: 0.991018182 (/tmp/trace1/metadata_1), 0, 0, , , 0, 0x0, MODE_UNKNOWN { channel = "kernel", name = "syscall_exit", event_id = 1, int = 4, long = 8, pointer = 8, size_t = 8, alignment = 8 }
metadata.core_marker_format: 0.991028275 (/tmp/trace1/metadata_1), 0, 0, , , 0, 0x0, MODE_UNKNOWN { channel = "kernel", name = "syscall_exit", format = "ret %ld" }
metadata.core_marker_id: 0.991033091 (/tmp/trace1/metadata_1), 0, 0, , , 0, 0x0, MODE_UNKNOWN { channel = "metadata", name = "core_marker_format", event_id = 1, int = 4, long = 8, pointer = 8, size_t = 8, alignment = 8 }
metadata.core_marker_format: 0.991037695 (/tmp/trace1/metadata_1), 0, 0, , , 0, 0x0, MODE_UNKNOWN { channel = "metadata", name = "core_marker_format", format = "channel %s name %s format %s" }
metadata.core_marker_id: 0.991042347 (/tmp/trace1/metadata_1), 0, 0, , , 0, 0x0, MODE_UNKNOWN { channel = "metadata", name = "core_marker_id", event_id = 0, int = 4, long = 8, pointer = 8, size_t = 8, alignment = 8 }
kernel.syscall_exit: 0.991045991 (/tmp/trace1/kernel_3), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 6 }
metadata.core_marker_format: 0.991047180 (/tmp/trace1/metadata_1), 0, 0, , , 0, 0x0, MODE_UNKNOWN { channel = "metadata", name = "core_marker_id", format = "channel %s name %s event_id %hu int #1u%zu long #1u%zu pointer #1u%zu size_t #1u%zu alignment #1u%u" }
metadata.core_marker_id: 0.991052670 (/tmp/trace1/metadata_1), 0, 0, , , 0, 0x0, MODE_UNKNOWN { channel = "kernel", name = "syscall_entry", event_id = 0, int = 4, long = 8, pointer = 8, size_t = 8, alignment = 8 }
kernel.syscall_exit: 0.991055401 (/tmp/trace1/kernel_3), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 0 }
metadata.core_marker_format: 0.991057117 (/tmp/trace1/metadata_1), 0, 0, , , 0, 0x0, MODE_UNKNOWN { channel = "kernel", name = "syscall_entry", format = "ip #p%ld syscall_id #2u%u" }
kernel.syscall_exit: 0.991063935 (/tmp/trace1/kernel_3), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 0 }
kernel.syscall_exit: 0.991065411 (/tmp/trace1/kernel_3), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 1 }
kernel.syscall_exit: 0.991066830 (/tmp/trace1/kernel_3), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 2 }
kernel.syscall_exit: 0.991068682 (/tmp/trace1/kernel_3), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 0 }
kernel.syscall_exit: 0.991203430 (/tmp/trace1/kernel_3), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 718741504 }
kernel.syscall_exit: 0.991255070 (/tmp/trace1/kernel_3), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 0 }
kernel.syscall_exit: 0.991300875 (/tmp/trace1/kernel_3), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 8060 }
kernel.syscall_exit: 0.991322296 (/tmp/trace1/kernel_2), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 0 }
kernel.syscall_exit: 0.991333195 (/tmp/trace1/kernel_2), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 0 }
kernel.syscall_exit: 0.991359811 (/tmp/trace1/kernel_2), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 6 }
kernel.syscall_exit: 0.991401977 (/tmp/trace1/kernel_1), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 0 }
kernel.syscall_exit: 0.996884007 (/tmp/trace1/kernel_2), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 1 }
kernel.syscall_exit: 0.996902622 (/tmp/trace1/kernel_2), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 48 }
kernel.syscall_exit: 0.996924692 (/tmp/trace1/kernel_2), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 0 }
kernel.syscall_exit: 0.996927265 (/tmp/trace1/kernel_2), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 0 }
kernel.syscall_exit: 0.996956393 (/tmp/trace1/kernel_2), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 2 }
kernel.syscall_exit: 0.996974647 (/tmp/trace1/kernel_2), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ret = 0 }

-----Original Message-----
From: Alexandre Montplaisir [mailto:alexandre.montplaisir at polymtl.ca]
Sent: Thu 10/6/2011 7:13 AM
To: Venkatesh Babu Chitlur Srinivasa (vchitlur)
Cc: ltt-dev at lists.casi.polymtl.ca
Subject: Re: [ltt-dev] Tracing syscall_entry not working

On 11-10-05 01:09 PM, Venkatesh Babu Chitlur Srinivasa (vchitlur) wrote:
> I followed the instructions in 
> http://git.lttng.org/?p=lttv.git;a=blob_plain;f=LTTngManual.html#install
> lttng to enable the tracing for only the system call enter/exits on
> MontaVista kernel. So I loaded only the  ltt-* modules and
> syscall-trace.
>
> I did mount debugfs and enabled only syscall enter/exit.
>
> echo 1 > /mnt/debugfs/ltt/markers/kernel/syscall_entry/enable
> echo 1 > /mnt/debugfs/ltt/markers/kernel/syscall_exit/enable
>
> lttctl -C -w /tmp/trace1 trace1 trace1
>
> lttctl -D trace1
>
> lttv -mtextDump -t /tmp/trace1
>
> But it is only tracing the syscall exits but not syscall enter.
>
> kernel.syscall_exit: 0.991063935 (/tmp/trace1/kernel_3), 0, 0, , , 0,
> 0x0, MODE_UNKNOWN { ret = 0 }
> kernel.syscall_exit: 0.991065411 (/tmp/trace1/kernel_3), 0, 0, , , 0,
> 0x0, MODE_UNKNOWN { ret = 1 }
> kernel.syscall_exit: 0.991066830 (/tmp/trace1/kernel_3), 0, 0, , , 0,
> 0x0, MODE_UNKNOWN { ret = 2 }
> kernel.syscall_exit: 0.991068682 (/tmp/trace1/kernel_3), 0, 0, , , 0,
> 0x0, MODE_UNKNOWN { ret = 0 }
> kernel.syscall_exit: 0.991203430 (/tmp/trace1/kernel_3), 0, 0, , , 0,
> 0x0, MODE_UNKNOWN { ret = 718741504 }
> kernel.syscall_exit: 0.991255070 (/tmp/trace1/kernel_3), 0, 0, , , 0,
> 0x0, MODE_UNKNOWN { ret = 0 }
> kernel.syscall_exit: 0.991300875 (/tmp/trace1/kernel_3), 0, 0, , , 0,
> 0x0, MODE_UNKNOWN { ret = 8060 }
> kernel.syscall_exit: 0.991322296 (/tmp/trace1/kernel_2), 0, 0, , , 0,
> 0x0, MODE_UNKNOWN { ret = 0 }
>
> Even when I loaded the all the other trace modules and did ltt-armall,
> still I am seeing the traces for only syscall_exit but not for
> syscall_enter. Am I missing something here?

Just out of curiosity, are you grep'ing to get this output? The event
name is syscall_entry, not _enter, so grep obviously wouldn't find anything.

-- 
Alexandre Montplaisir
DORSAL lab,
École Polytechnique de Montréal

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