Messages in this thread | | | Date | Thu, 30 May 2019 20:57:09 +0800 | From | Leo Yan <> | Subject | Re: [PATCHv3 00/12] perf tools: Display eBPF code in intel_pt trace |
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Hi Jiri,
On Thu, May 30, 2019 at 02:07:10PM +0200, Jiri Olsa wrote: > On Thu, May 30, 2019 at 06:54:39PM +0800, Leo Yan wrote: > > Hi Jiri, > > > > On Wed, May 08, 2019 at 03:19:58PM +0200, Jiri Olsa wrote: > > > hi, > > > this patchset adds dso support to read and display > > > bpf code in intel_pt trace output. I had to change > > > some of the kernel maps processing code, so hopefully > > > I did not break too many things ;-) > > > > > > It's now possible to see bpf code flow via: > > > > > > # perf-with-kcore record pt -e intel_pt//ku -- sleep 1 > > > # perf-with-kcore script pt --insn-trace --xed > > > > This is very interesting work for me! > > > > I want to verify this feature with Arm CoreSight trace, I have one > > question so that I have more direction for the tesing: > > > > What's the bpf program you are suing for the testing? e.g. some > > testing program under the kernel's folder $kernel/samples/bpf? > > Or you uses perf command to launch bpf program? > > for this I was using tools/testing/selftests/bpf/test_verifier > > I isolated some tests and ran the perf on top of them, like: > > # perf-with-kcore record pt -e intel_pt//ku -- ./test_verifier ...
Thanks a lot for sharing the info and quick responsing.
I tried to use the program $kernel/samples/bpf/sampleip to verify this patch set, but seems eBPF dso is not contained properly; below is my detailed steps:
# In the first tty # cd $kernel/samples/bpf/ # ./sampleip -F 200 20 => sample ip with 200Hz for 20s
# In the second tty # perf-with-kcore record arm_test -e cs_etm/@20070000.etr/uk -- sleep 1
If I output DSO info with report command it give below info, which doesn't contain any info for eBPF DSO?
# perf-with-kcore report arm_test -F,dso
# Samples: 6M of event 'branches:ku' # Event count (approx.): 6340896 # # Shared Object # .................. # [kernel.kallsyms] ld-2.28.so libc-2.28.so libpthread-2.28.so perf sleep [unknown]
> I had to add some small sleep before the test_verifier exit, > so the perf bpf thread could catch up and download the program > details before test_verifier exited.
This seems to me for a 'real' eBPF program, do we also need extra sleep so that perf bpf can save dso properly?
BTW, I have another question: to display eBPF code, except this feature can be used by hardware tracing (e.g. intel_pt), it also can be used by other PMU events and timer events, right?
Thanks, Leo Yan
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