On Tue, Mar 4, 2014 at 12:34 PM, Yuri Gribov <[email protected]> wrote:
> > 2) Currently the top frame in the allocation stack is a function in ASan > > runtime, so I assume you mean malloc_context_size=2. > > Right. > > > I agree it's not wise to call _UnwindBacktrace if we're interested only > in the top frame. > > ... > > I don't like the idea of > > introducing a special case for malloc_context_size=1 in our malloc/new > interceptors > > So just to clarify: you are ok with special-casing > malloc_context_size=2 but not malloc_context_size=1 ? > I don't like the idea of special-casing malloc_context_size=2 (fetching both current and caller PC in the malloc/new interceptor, and passing them both to function/macros doing the unwinding, so that it wouldn't do the actual unwinding if malloc_context_size=2). We can go this path, but only if there's a performance benefit at the end. > > > Do you have > > any stats/justifications for that proposal? E.g. is ASan unwinder > visible in > > profile for malloc-intensive application even for small values of > > malloc_context_size? > > I did run malloc-intensive code a couple of months ago with malloc > contexts turned on and it was horribly slow. Is there are a reason why you can't compile your code/libraries with -fno-omit-frame-pointer and use a "fast" unwinder? We run very malloc-intensive applications, and fast unwinder (with enabled contexts) doesn't cause any significant slowdown. > Unfortunately I don't > remember whether I tried to reduce default size or just turned it off > alltogether... > > -Y > > -- > You received this message because you are subscribed to the Google Groups > "address-sanitizer" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- Alexey Samsonov, MSK -- You received this message because you are subscribed to the Google Groups "address-sanitizer" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
