Hi Jeremy,
On Wed, 28 Aug 2013 10:57:08 -0400, Jeremy Eder wrote:
> On 130813 11:20:52, Namhyung Kim wrote:
>> @@ -579,6 +587,8 @@ out:
>> pthread_cond_signal(&recorder_ready_cond);
>> pthread_mutex_unlock(&recorder_mutex);
>> }
>> +
>> + pr_debug2("done with %ld bytes\n", (long)byte_written);
>> return fra;
>> }
>>
>
> Hmm, I already had hunk #3 in your git tree v4.
Oops, sorry about that.
>
>> @@ -1139,12 +1149,12 @@ retry:
>> return record;
>> }
>>
>> - munmap(fra->map, pevent_get_page_size(ftrace->pevent));
>> - fra->map = NULL;
>> -
>> if (fra->done)
>> return NULL;
>>
>> + munmap(fra->map, pevent_get_page_size(ftrace->pevent));
>> + fra->map = NULL;
>> +
>> fra->offset += pevent_get_page_size(ftrace->pevent);
>> if (fra->offset >= fra->size) {
>> /* EOF */
>
>
> After patching your tree with just the first 2 hunks, I'm able to
> get ftrace-style function graphing out of perf.
>
> # ./perf ftrace record df
> Filesystem 1K-blocks Used Available Use% Mounted on
> <snip>...
>
> # ./perf --no-pager ftrace show | head -20
> overriding event (11) ftrace:funcgraph_entry with new print handler
> overriding event (10) ftrace:funcgraph_exit with new print handler
> 2) 0.686 us | finish_task_switch();
> 2) 0.260 us | finish_wait();
> 2) | mutex_lock() {
> 2) 0.211 us | _cond_resched();
> 2) 1.170 us | }
> 2) 0.319 us | generic_pipe_buf_confirm();
> 2) 0.261 us | generic_pipe_buf_map();
> 2) 0.129 us | generic_pipe_buf_unmap();
> 2) 0.747 us | anon_pipe_buf_release();
> 2) 0.138 us | mutex_unlock();
> 2) | __wake_up_sync_key() {
> 2) 0.279 us | _raw_spin_lock_irqsave();
> 2) 0.135 us | __wake_up_common();
> 2) 0.133 us | __lock_text_start();
> 2) 3.386 us | }
> 2) | kill_fasync() {
> 2) | smp_reschedule_interrupt() {
> 2) 0.130 us | kvm_guest_apic_eoi_write();
>
> Nice.
Glad to see this. :)
>
> Not sure if you intend to move all ftrace functionality over to
> perf ftrace, but the function graph timings is a great start and something
> sorely
> missing.
>
> Do you intend to add -e event support or -l function-specific options ? In
> the real
> world, without filtering on events or functions, I've had systems hang, plus
> performance impact is too great.
>
> A common invocation of ftrace via trace-cmd is:
> # trace-cmd record -p function_graph -e irq:* -l do_IRQ ping -c1
> www.redhat.com
>
> So possible perf equivalent?
> # ./perf ftrace record -e irq:* -e do_IRQ ping -c1 www.redhat.com
Yes I'm considering adding more features in trace-cmd to perf ftrace.
The function filtering is the one in the highest priority. I also want
to add support for other events but it needs bit more thinking.
Thanks,
Namhyung
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