Messages in this thread | | | From | "Hunter, Adrian" <> | Subject | RE: [PATCH 1/5] perf tools: Add fallback functions for cases where cpumode is insufficient | Date | Mon, 5 Nov 2018 19:53:17 +0000 |
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> -----Original Message----- > From: Arnaldo Carvalho de Melo [mailto:acme@kernel.org] > Sent: Monday, November 5, 2018 9:36 PM > To: Hunter, Adrian <adrian.hunter@intel.com> > Cc: Jiri Olsa <jolsa@redhat.com>; Andi Kleen <ak@linux.intel.com>; linux- > kernel@vger.kernel.org; leo.yan@linaro.org; David Miller > <davem@davemloft.net>; Mathieu Poirier <mathieu.poirier@linaro.org> > Subject: Re: [PATCH 1/5] perf tools: Add fallback functions for cases where > cpumode is insufficient > > Em Mon, Nov 05, 2018 at 07:21:44PM +0000, Hunter, Adrian escreveu: > > > In Monday, November 5, 2018 7:30 PM, Arnaldo Carvalho de Melo wrote > <SNIP> > > > > +struct map *thread__find_map_fallback(struct thread *thread, u8 > > > cpumode, > > > > + u64 addr, struct addr_location *al) { > > > > You named one as _fallback... > > > > > + struct map *map = thread__find_map(thread, cpumode, addr, al); > > > > + struct machine *machine = thread->mg->machine; > > > > + u8 addr_cpumode = machine__addr_cpumode(machine, cpumode, > > > addr); > > > > + > > > > + if (map || addr_cpumode == cpumode) > > > > + return map; > > > > + > > > > + return thread__find_map(thread, addr_cpumode, addr, al); } > > > > + > > > > struct symbol *thread__find_symbol(struct thread *thread, u8 > cpumode, > > > > u64 addr, struct addr_location *al) { @@ - > > > 1585,6 +1603,15 @@ > > > > struct symbol *thread__find_symbol(struct thread *thread, u8 > cpumode, > > > > return al->sym; > > > > } > > > > > +struct symbol *thread__find_symbol_fb(struct thread *thread, u8 > > > cpumode, > > > > + u64 addr, struct addr_location *al) > > > > ... and the other as _fb, make it consistent, please. > > > ok > > > > > +{ > > > > + al->sym = NULL; > > > > + if (thread__find_map_fallback(thread, cpumode, addr, al)) > > > > + al->sym = map__find_symbol(al->map, al->addr); > > > > + return al->sym; > > > > +} > > > > > /* > > > > * Callers need to drop the reference to al->thread, obtained in > > > > * machine__findnew_thread() > > > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c > > > > index 111ae858cbcb..04edc0eac376 100644 > > > > --- a/tools/perf/util/machine.c > > > > +++ b/tools/perf/util/machine.c > > > > @@ -2542,6 +2542,46 @@ int machine__get_kernel_start(struct > > > > machine > > > *machine) > > > > return err; > > > > } > > > > > +/* > > > > + * machine__single_ku_as - Machine has same address space for > > > > +kernel > > > and user. > > > > + * @machine: machine object > > > > + * > > > > + * Some architectures have a single address space for kernel and > > > > +user addresses, > > > > + * which makes it possible to determine if an address is in > > > > +kernel space or user > > > > + * space. > > > > + */ > > > > +static bool machine__single_ku_as(struct machine *machine) { > > > > + return strcmp(perf_env__arch(machine->env), "sparc"); } > > > > Can we avoid having this strcmp be done repeatedly? > > > It is only done if there are mapping errors > > > > Can we avoid having this strcmp be done repeatedly? I.e. just make > > this a > > > boolean initialized at session start, when machine->env is setup, so > > > we'd > > > have: > > > > machine->single_address_space > > > > Instead of a function? > > > Sure thing. > > Thanks > > > > > > > Also have you considered making this fallback to be performed only > > > from code that is that arch specific? > > > > > > I.e. the code that supports branch samples/stacks is x86_86 specific > > > at this point and thus only in that case we would call the routines > > > that perform the fallback, which, in turn, wouldn't need to check for > "sparc"? > > > I will look at it, but theoretically someone could be processing x86 > > data but doing it on a machine of a different architecture. > > Right, that should be supported, yes. What I meant was that when > processing perf.data file with samples where the cpumode can't be inferred, > we should use the fallback routines. > > It is super unfortunate that we have addresses without a accompanying > cpumode :-\ Don't you think those coulde be fixed somehow? If this comes > from things synthesized from Intel PT traces, then we can use the address > ranges for kernel/userspace to derive that before hitting the core code, that > would be fed with addr/cpumode pairs, just like we have hdr.misc & > USER/KERNEL and the PERF_CONTEXT_ markers in callchains.
Yes we will probably need to look at that, but at the moment I would like a fix for stable.
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