Messages in this thread | | | Date | Thu, 19 Apr 2012 10:33:32 -0700 | From | Arun Sharma <> | Subject | Re: [PATCH] perf, x86: Disable sanity check |
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On 4/18/12 10:22 PM, Frederic Weisbecker wrote:
> So rbp is part of the JIT stack but not rsp? > Do you have a practical example of that? I must confess I don't know > much about JIT stack.
Nothing specific to JITs here. Any time an app has two stacks S1 and S2 (with S1 at a lower address and S2 at a higher address) and %rsp at the time of a perf event is pointing to S2, we don't get traces beyond S2.
| | | | | 0x1000000 | <-- %rbp | | | | S2: 0x2000000 | | <-- %rsp | | | | | | | frame3 | | | | frame2 | | | S1: 0x1000000 | frame1 | | | | | | | | |
gdb is able to show:
(gdb) bt <frame at 0x2000000> frame1 frame2 frame3 frame4 ..
just fine.
In our use case, there may be multiple transitions between S1 and S2. For eg: frame4 could be on S2 (i.e 0x2xxxxxx range).
-Arun
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