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Re: missing sytemtap kernel.trace("net*") on newer Fedora kernels
- From: William Cohen <wcohen at redhat dot com>
- To: Josh Stone <jistone at redhat dot com>, systemtap at sourceware dot org
- Date: Thu, 12 Jun 2014 11:52:18 -0400
- Subject: Re: missing sytemtap kernel.trace("net*") on newer Fedora kernels
- Authentication-results: sourceware.org; auth=none
- References: <5398CB2C dot 9000001 at redhat dot com> <5398E088 dot 2060202 at redhat dot com>
On 06/11/2014 07:04 PM, Josh Stone wrote:
> On 06/11/2014 02:33 PM, William Cohen wrote:
>> I was looking at the perf netdev-times script:
>>
>> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/tools/perf/scripts/python/bin/netdev-times-record
>>
>> Which uses the following perf tracepoints:
>>
>> #!/bin/bash
>> perf record -e net:net_dev_xmit -e net:net_dev_queue \
>> -e net:netif_receive_skb -e net:netif_rx \
>> -e skb:consume_skb -e skb:kfree_skb \
>> -e skb:skb_copy_datagram_iovec -e napi:napi_poll \
>> -e irq:irq_handler_entry -e irq:irq_handler_exit \
>> -e irq:softirq_entry -e irq:softirq_exit \
>> -e irq:softirq_raise $@
>>
>>
>> On the rhel7 kernel all of the tracepoints are available, However,
>> on Fedora 20 none of the kernel.trace("net*"), kernel.trace("*skb*"),
>> or kernel.trace("napi_poll") tracepoints are there.
>>
>> Has anyone else noticed the missing tracepoints on Fedora 20?
>
> I see all of these on kernel-3.14.5-200.fc20.x86_64.
>
> You can see all the gory tracepoint-detecting details from your listing
> with "stap -vvvv --poison-cache ...". For instance, napi_poll should
> come from include/trace/events/napi.h. On my system it finds that
> header under both /lib/modules and /usr/src/debug, but I even tried
> moving the debug tree aside, and it still found the tracepoint.
>
I upgraded and rebooted to the kernel-3.14.6-200.fc20.x86_64 and the tracepoints seem to be in this kernel. Weird. Now things are working I am going to assume that something got messed on in the kernel-devel install for 3.14.5-200.fc20.x86_64.
-Will