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Re: missing sytemtap kernel.trace("net*") on newer Fedora kernels
- From: Josh Stone <jistone at redhat dot com>
- To: William Cohen <wcohen at redhat dot com>, systemtap at sourceware dot org
- Date: Wed, 11 Jun 2014 16:04:40 -0700
- 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>
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.