thanks. That will be helpful. David
On Fri, Oct 5, 2012 at 2:09 PM, Dehao Chen <de...@google.com> wrote: > Sure, I'll add a detailed documentation in a gcc wiki page. > > Dehao > > On Fri, Oct 5, 2012 at 2:01 PM, Xinliang David Li <davi...@google.com> wrote: >> Dehao, the file auto-profile.c has some high level description of >> aFDO, but I think it is too sparse. Can you write up a gcc wiki page >> and point the details to that page in auto-profile.c? >> >> The documentation should focus more on the differences (mainly the >> profile-use phase) between sample based FDO and instrumentation based >> FDO. The description there should explain various autoFDO specific >> tunings in cgraph build, ipa-inline, cloning, introduction of >> total_count and rationale etc. The main source of difference comes >> from differences in the points of profiling, but some small examples >> would help. >> >> Most of the changes guarded by flag_auto_profile need some comments. >> >> thanks, >> >> David >> >> On Fri, Sep 28, 2012 at 5:22 PM, Dehao Chen <de...@google.com> wrote: >>> Hi, >>> >>> This patch implements the fine-graind AutoFDO optimizations for GCC. >>> It uses linux perf to collect sample profiles, and uses debug info to >>> represent the profile. In GCC, it uses the profile to annotate CFG to >>> drive FDO. This can bring 50% to 110% of the speedup derived by >>> traditional instrumentation based FDO. (Average is between 70% to 80% >>> for many CPU intensive applications). Comparing with traditional FDO, >>> AutoFDO does not require instrumentation. It just need to have an >>> optimized binary with debug info to collect the profile. >>> >>> This patch has passed bootstrap and gcc regression tests as well as >>> tested with crosstool. Okay for google branches? >>> >>> If people in up-stream find this feature interesting, I'll spend some >>> time to port this to trunk and try to opensource the tool to generate >>> profile data file. >>> >>> Dehao >>> >>> The patch can also be viewed from: >>> >>> http://codereview.appspot.com/6567079 >>> >>> gcc/ChangeLog.google-4_7: >>> 2012-09-28 Dehao Chen <de...@dehao.com> >>> >>> * cgraphbuild.c (build_cgraph_edges): Handle AutoFDO profile. >>> (rebuild_cgraph_edges): Likewise. >>> * cgraph.c (cgraph_clone_node): Likewise. >>> (clone_function_name): Likewise. >>> * cgraph.h (cgraph_node): New field. >>> * tree-pass.h (pass_ipa_auto_profile): New pass. >>> * cfghooks.c (make_forwarder_block): Handle AutoFDO profile. >>> * ipa-inline-transform.c (clone_inlined_nodes): Likewise. >>> * toplev.c (compile_file): Likewise. >>> (process_options): Likewise. >>> * debug.h (auto_profile_debug_hooks): New. >>> * cgraphunit.c (cgraph_finalize_compilation_unit): Handle AutoFDO >>> profile. >>> (cgraph_copy_node_for_versioning): Likewise. >>> * regs.h (REG_FREQ_FROM_BB): Likewise. >>> * gcov-io.h: (GCOV_TAG_AFDO_FILE_NAMES): New. >>> (GCOV_TAG_AFDO_FUNCTION): New. >>> (GCOV_TAG_AFDO_MODULE_GROUPING): New. >>> * ira-int.h (REG_FREQ_FROM_EDGE_FREQ): Handle AutoFDO profile. >>> * ipa-inline.c (edge_hot_enough_p): Likewise. >>> (edge_badness): Likewise. >>> (inline_small_functions): Likewise. >>> * dwarf2out.c (auto_profile_debug_hooks): New. >>> * opts.c (common_handle_option): Handle AutoFDO profile. >>> * timevar.def (TV_IPA_AUTOFDO): New. >>> * predict.c (compute_function_frequency): Handle AutoFDO profile. >>> (rebuild_frequencies): Handle AutoFDO profile. >>> * auto-profile.c (struct gcov_callsite_pos): New. >>> (struct gcov_callsite): New. >>> (struct gcov_stack): New. >>> (struct gcov_function): New. >>> (struct afdo_bfd_name): New. >>> (struct afdo_module): New. >>> (afdo_get_filename): New. >>> (afdo_get_original_name_size): New. >>> (afdo_get_bfd_name): New. >>> (afdo_read_bfd_names): New. >>> (afdo_stack_hash): New. >>> (afdo_stack_eq): New. >>> (afdo_function_hash): New. >>> (afdo_function_eq): New. >>> (afdo_bfd_name_hash): New. >>> (afdo_bfd_name_eq): New. >>> (afdo_bfd_name_del): New. >>> (afdo_module_hash): New. >>> (afdo_module_eq): New. >>> (afdo_module_num_strings): New. >>> (afdo_add_module): New. >>> (read_aux_modules): New. >>> (get_inline_stack_size_by_stmt): New. >>> (get_inline_stack_size_by_edge): New. >>> (get_function_name_from_block): New. >>> (get_inline_stack_by_stmt): New. >>> (get_inline_stack_by_edge): New. >>> (afdo_get_function_count): New. >>> (afdo_set_current_function_count): New. >>> (afdo_add_bfd_name_mapping): New. >>> (afdo_add_copy_scale): New. >>> (get_stack_count): New. >>> (get_stmt_count): New. >>> (afdo_get_callsite_count): New. >>> (afdo_get_bb_count): New. >>> (afdo_annotate_cfg): New. >>> (read_profile): New. >>> (process_auto_profile): New. >>> (init_auto_profile): New. >>> (end_auto_profile): New. >>> (afdo_find_equiv_class): New. >>> (afdo_propagate_single_edge): New. >>> (afdo_propagate_multi_edge): New. >>> (afdo_propagate_circuit): New. >>> (afdo_propagate): New. >>> (afdo_calculate_branch_prob): New. >>> (auto_profile): New. >>> (gate_auto_profile_ipa): New. >>> (struct simple_ipa_opt_pass): New. >>> * auto-profile.h (init_auto_profile): New. >>> (end_auto_profile): New. >>> (process_auto_profile): New. >>> (afdo_set_current_function_count): New. >>> (afdo_add_bfd_name_mapping): New. >>> (afdo_add_copy_scale): New. >>> (afdo_calculate_branch_prob): New. >>> (afdo_get_callsite_count): New. >>> (afdo_get_bb_count): New. >>> * profile.c (compute_branch_probabilities): Handle AutoFDO profile. >>> (branch_prob): Likeise. >>> * loop-unroll.c (decide_unroll_runtime_iterations): Likewise. >>> * coverage.c (coverage_init): Likewise. >>> * tree-ssa-live.c (remove_unused_scope_block_p): Likewise. >>> * common.opt (fauto-profile): New. >>> * tree-inline.c (copy_bb): Handle AutoFDO profile. >>> (copy_edges_for_bb): Likewise. >>> (copy_cfg_body): Likewise. >>> * tree-profile.c (direct_call_profiling): Likewise. >>> (gate_tree_profile_ipa): Likewise. >>> * basic-block.h (EDGE_ANNOTATED): New field. >>> (BB_ANNOTATED): New field. >>> * tree-cfg.c (gimple_merge_blocks): Handle AutoFDO profile. >>> * passes.c (init_optimization_passes): Handle AutoFDO profile.
