High dependence on CPU performance about glmark2

[troosh]

Really need to look at the performance of the following tests:

1. buffer

 52.18% glmark2 glmark2 [.] SceneBuffer::update() 
 20.24% glmark2 glmark2 [.] Mesh::update_single_array(std::vector<std::pair<unsigned long, unsigned long>, std::allocator<std::pair<unsigned long, unsigned long> > > const&, unsigned long, unsigned long, unsigned long) 
 13.40% glmark2 libc-2.23.so [.] __memmove_avx_unaligned 
  1.04% glmark2 [kernel.kallsyms] [k] evergreen_irq_set

2. refract

 6.77% glmark2 libc-2.23.so [.] _int_free 
 6.51% glmark2 libstdc++.so.6.0.20 [.] __dynamic_cast 
 5.98% glmark2 libc-2.23.so [.] malloc 
 4.75% glmark2 libc-2.23.so [.] _int_malloc 
 3.41% glmark2 libstdc++.so.6.0.20 [.] __cxxabiv1::__si_class_type_info::__do_dyncast(long, __cxxabiv1::__class_type_info::__sub_kind, __cxxabiv1::__class_type_info const*, void const*, __cxxabiv1::__class_type_info const*, void const*, __cxxabiv1::__class_type_info::__dyncast_result&) const 
 3.29% glmark2 ld-2.23.so [.] do_lookup_x 
 2.87% glmark2 libstdc++.so.6.0.20 [.] std::locale::locale() 
 2.85% glmark2 libstdc++.so.6.0.20 [.] __cxxabiv1::__vmi_class_type_info::__do_dyncast(long, __cxxabiv1::__class_type_info::__sub_kind, __cxxabiv1::__class_type_info const*, void const*, __cxxabiv1::__class_type_info const*, void const*, __cxxabiv1::__class_type_info::__dyncast_result&) const 
 2.34% glmark2 libstdc++.so.6.0.20 [.] std::locale::~locale() 
 2.31% glmark2 libstdc++.so.6.0.20 [.] std::locale::operator=(std::locale const&) 
 1.80% glmark2 libc-2.23.so [.] __strcmp_sse2_unaligned 
 1.63% glmark2 libstdc++.so.6.0.20 [.] bool std::has_facet<std::num_get<char, std::istreambuf_iterator<char, std::char_traits<char> > > >(std::locale const&) 
 1.46% glmark2 libc-2.23.so [.] memchr 
 1.32% glmark2 libc-2.23.so [.] __GI_____strtof_l_internal 
 1.27% glmark2 libstdc++.so.6.0.20 [.] bool std::has_facet<std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > > >(std::locale const&) 
 1.21% glmark2 ld-2.23.so [.] strcmp 
 1.16% glmark2 libstdc++.so.6.0.20 [.] std::locale::id::_M_id() const 
 1.16% glmark2 libstdc++.so.6.0.20 [.] std::istreambuf_iterator<char, std::char_traits<char> > std::num_get<char, std::istreambuf_iterator<char, std::char_traits<char> > >::_M_extract_int<unsigned int>(std::istreambuf_iterator<char, std::char_traits<char> >, std::istreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, std::_Ios_Iostate&, unsigned int&) const 
 1.10% glmark2 libstdc++.so.6.0.20 [.] std::basic_ios<char, std::char_traits<char> >::_M_cache_locale(std::locale const&) 
 1.02% glmark2 libc-2.23.so [.] __memcpy_avx_unaligned 
 0.99% glmark2 glmark2 [.] split_normal(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char, std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&) 
 0.99% glmark2 glmark2 [.] Mesh::set_attrib(unsigned int, LibMatrix::tvec3<float> const&, std::vector<float, std::allocator<float> >*) 
 0.96% glmark2 libstdc++.so.6.0.20 [.] std::num_get<char, std::istreambuf_iterator<char, std::char_traits<char> > > const& std::use_facet<std::num_get<char, std::istreambuf_iterator<char, std::char_traits<char> > > >(std::locale const&) 
 0.96% glmark2 libstdc++.so.6.0.20 [.] std::locale::_S_initialize() 
 0.96% glmark2 glmark2 [.] Util::split(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, char, std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&, Util::SplitMode) 
 0.96% glmark2 libstdc++.so.6.0.20 [.] std::basic_istream<char, std::char_traits<char> >& std::getline<char, std::char_traits<char>, std::allocator<char> >(std::basic_istream<char, std::char_traits<char> >&, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, char) 
 0.89% glmark2 libc-2.23.so [.] __memmove_avx_unaligned 
 0.84% glmark2 libstdc++.so.6.0.20 [.] std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) 
 0.82% glmark2 libstdc++.so.6.0.20 [.] std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > > const& std::use_facet<std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > > >(std::locale const&) 
 0.82% glmark2 libstdc++.so.6.0.20 [.] std::num_get<char, std::istreambuf_iterator<char, std::char_traits<char> > >::_M_extract_float(std::istreambuf_iterator<char, std::char_traits<char> >, std::istreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, std::_Ios_Iostate&, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&) const 
 0.82% glmark2 libstdc++.so.6.0.20 [.] std::ctype<char> const& std::use_facet<std::ctype<char> >(std::locale const&) 
 0.79% glmark2 libstdc++.so.6.0.20 [.] std::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_mutate(unsigned long, unsigned long, unsigned long) 
 0.76% glmark2 libstdc++.so.6.0.20 [.] std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, unsigned long, std::allocator<char> const&) 
 0.73% glmark2 libstdc++.so.6.0.20 [.] std::basic_ios<char, std::char_traits<char> >::init(std::basic_streambuf<char, std::char_traits<char> >*) 
 0.73% glmark2 glmark2 [.] std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >::_M_insert_aux(__gnu_cxx::__normal_iterator<std::basic_string<char, std::char_traits<char>, std::allocator<char> >*, std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) 
 0.68% glmark2 libstdc++.so.6.0.20 [.] std::ios_base::_M_init() 
 0.67% glmark2 libGL.so.1.2.0 [.] driConvertConfigs 

In other tests, first of all, most problems with user libraries (Mesa, libpng/libz, libpthread) and the kernel (DRM).

[afrantzis]

Hi! Thank you for this very interesting analysis. After your initial report I started taking a look at the CPU usage (I mostly used valgrind/callgrind), and, like you, noticed that in many cases the primary CPU consumer was not glmark2 itself, but rather some other part of the graphics stack. The CPU usage from libpng/libz shouldn't be a concern, since the textures are decoded at setup time and shouldn't affect benchmarking results. The CPU usage from drivers, and its effect on the benchmarks is actually something that we want reflected in the benchmark results.

There are still cases like the ones you mention in the second comment where the CPU usage lies predominantly in glmark2 itself. I have started looking into these and I will report progress in this issue.

[afrantzis]

I have pushed a performance improvement in 5b0f603 that helps with the CPU usage in the buffer scene. Looking at the refract scene, the majority of the CPU usage is in the scene setup code, so it shouldn't affect the benchmark results (of course, it would be good to improve it anyway).