Messages in this thread | | | Date | Wed, 7 Jul 2021 11:41:31 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf intel-pt: Add a config for max loops without consuming a packet |
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Em Thu, Jul 01, 2021 at 10:54:53AM -0700, Andi Kleen escreveu: > > On 7/1/2021 10:51 AM, Adrian Hunter wrote: > > The Intel PT decoder limits the number of unconditional branches (e.g. > > jmps) decoded without consuming any trace packets. Generally, a loop > > needs a conditional branch which generates a TNT packet, whereas a > > "ret" instruction will generate a TIP or TNT packet. So exceeding > > the limit is assumed to be a never-ending loop, which can happen if > > there has been a decoding error putting the decoder at the wrong place in > > the code. > > > > Up until now, the limit of 10000 has been enough but some analytic > > purposes have been reported to exceed that. > > > > Increase the limit to 100000, and make it configurable via perf config > > intel-pt.max-loops. Also amend the "Never-ending loop" message to > > mention the configuration entry. > > > > Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> > > > Thanks. That is useful. > > > Reviewed-by: Andi Kleen <ak@linux.intel.com>
Thanks, applied.
- Arnaldo
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