marxin
commented
2 months ago I format to mention that the object files are using ZSTD compression for the debug info sections.
Open marxin opened 2 months ago
marxin
commented
2 months ago I format to mention that the object files are using ZSTD compression for the debug info sections.
marxin
commented
2 months ago And my perf report looks as follows:
25.61% ld.mold mold [.] mold::elf::MergeableSection<mold::elf::X86_64>::get_fragment(long)
10.70% ld.mold mold [.] mold::elf::InputSection<mold::elf::X86_64>::apply_reloc_nonalloc(mold::elf::Context<mold::elf::X86_64>&, unsigned char*)
9.97% ld.mold libc.so.6 [.] __memcmp_evex_movbe
8.35% ld.mold mold [.] mold::elf::MergedSection<mold::elf::X86_64>::insert(mold::elf::Context<mold::elf::X86_64>&, std::basic_string_view<char, std::char_traits<char> >, unsigned long, long) [clone .isra.0]
5.43% ld.mold mold [.] mold::elf::MergeableSection<mold::elf::X86_64>::split_contents(mold::elf::Context<mold::elf::X86_64>&)
4.89% ld.mold mold [.] blake3_hash_many_avx512
2.65% ld.mold mold [.] mold::elf::find_null(std::basic_string_view<char, std::char_traits<char> >, long, long) [clone .lto_priv.17] [clone .lto_priv.0]
2.20% ld.mold mold [.] mold::elf::InputSection<mold::elf::X86_64>::get_fragment(mold::elf::Context<mold::elf::X86_64>&, mold::elf::ElfRel<mold::elf::X86_64> const&) [clone .isra.0]
2.05% ld.mold libzstd.so.1.5.6 [.] 0x000000000006c393
1.95% ld.mold mold [.] mold::elf::InputSection<mold::elf::X86_64>::record_undef_error(mold::elf::Context<mold::elf::X86_64>&, mold::elf::ElfRel<mold::elf::X86_64> const&)
1.04% ld.mold mold [.] mold::elf::InputSection<mold::elf::X86_64>::get_tombstone(mold::elf::Symbol<mold::elf::X86_64>&, mold::elf::SectionFragment<mold::elf::X86_64>*)
0.90% ld.mold mold [.] mold::elf::MergeableSection<mold::elf::X86_64>::get_contents(long)
0.71% ld.mold libc.so.6 [.] __memchr_evex
0.71% ld.mold libc.so.6 [.] __memmove_avx512_unaligned_erms
0.67% ld.mold mold [.] mold::Integer<long, (std::endian)1234, 8>::operator long() const [clone .isra.0]
0.55% ld.mold mold [.] mold::elf::Symbol<mold::elf::X86_64>::get_addr(mold::elf::Context<mold::elf::X86_64>&, long) const
0.51% ld.mold mold [.] mold::elf::MergedSection<mold::elf::X86_64>::compute_section_size(mold::elf::Context<mold::elf::X86_64>&)::{lambda(long)#1}::operator()(long) const
rui314
commented
2 months ago I ran a quick benchmark again and the number seems consistent.
ruiu@odyssey:~/llvm-project/b$ taskset -c 0-31 hyperfine 'mold @rsp' 'ld.lld @rsp'
Benchmark 1: mold @rsp
Time (mean ± σ): 1.636 s ± 0.018 s [User: 0.005 s, System: 0.003 s]
Range (min … max): 1.609 s … 1.663 s 10 runs
Benchmark 2: ld.lld @rsp
Time (mean ± σ): 5.985 s ± 0.025 s [User: 27.125 s, System: 16.205 s]
Range (min … max): 5.946 s … 6.018 s 10 runs
Summary
mold @rsp ran
3.66 ± 0.04 times faster than ld.lld @rspInteresting! Can you please provide the output of bloaty for the linked binary? And perf report for Mold linker ;)
rui314
commented
2 months ago $ ~/bloaty/build/bloaty bin/clang-19
FILE SIZE VM SIZE
-------------- --------------
70.2% 2.85Gi 0.0% 0 .debug_info
6.0% 249Mi 0.0% 0 .debug_str
5.8% 240Mi 0.0% 0 .strtab
4.7% 196Mi 0.0% 0 .debug_line
4.6% 190Mi 49.5% 190Mi .text
2.7% 111Mi 29.1% 111Mi .rodata
1.4% 58.8Mi 0.0% 0 .symtab
1.3% 55.6Mi 0.0% 0 .debug_aranges
0.9% 38.6Mi 10.0% 38.6Mi .eh_frame
0.8% 35.3Mi 0.0% 0 .debug_rnglists
0.6% 23.8Mi 0.0% 0 .debug_abbrev
0.3% 12.1Mi 3.2% 12.1Mi .rela.dyn
0.2% 9.44Mi 2.5% 9.44Mi .eh_frame_hdr
0.2% 8.31Mi 2.2% 8.31Mi .data.rel.ro
0.2% 7.75Mi 2.0% 7.75Mi .dynstr
0.0% 0 0.7% 2.87Mi .bss
0.0% 1.92Mi 0.5% 1.92Mi .dynsym
0.0% 495Ki 0.1% 495Ki .gnu.hash
0.0% 429Ki 0.1% 429Ki .data
0.0% 315Ki 0.0% 0 .debug_line_str
0.0% 252Ki 0.1% 252Ki [27 Others]
100.0% 4.06Gi 100.0% 383Mi TOTALAnd here is my perf report.
+ 29.04% 0.19% mold [kernel.kallsyms] [k] asm_exc_page_fault
+ 28.50% 0.15% mold [kernel.kallsyms] [k] exc_page_fault
+ 28.03% 0.15% mold [kernel.kallsyms] [k] do_user_addr_fault
+ 27.46% 0.18% mold [kernel.kallsyms] [k] handle_mm_fault
+ 26.93% 0.29% mold [kernel.kallsyms] [k] __handle_mm_fault
+ 26.56% 0.07% mold [kernel.kallsyms] [k] handle_pte_fault
+ 21.83% 0.10% mold [kernel.kallsyms] [k] do_fault
+ 21.72% 0.88% mold libc.so.6 [.] __memmove_avx512_unaligned_erms
+ 17.52% 0.02% mold [kernel.kallsyms] [k] do_page_mkwrite
+ 17.48% 0.43% mold [kernel.kallsyms] [k] ext4_page_mkwrite
+ 16.63% 0.05% mold [kernel.kallsyms] [k] block_page_mkwrite
+ 16.08% 7.61% mold mold [.] mold::MergeableSection<mold::X86_64>::get_fragment(long)
+ 15.95% 0.04% mold [kernel.kallsyms] [k] mark_buffer_dirty
+ 15.91% 15.73% mold [kernel.kallsyms] [k] native_queued_spin_lock_slowpath
+ 15.81% 0.06% mold [kernel.kallsyms] [k] __block_commit_write
+ 15.70% 0.04% mold [kernel.kallsyms] [k] __folio_mark_dirty
+ 15.54% 0.00% mold [unknown] [k] 0000000000000000
+ 15.03% 0.03% mold [kernel.kallsyms] [k] __raw_spin_lock_irqsave
+ 15.03% 0.01% mold [kernel.kallsyms] [k] _raw_spin_lock_irqsave
+ 13.13% 7.72% mold mold [.] mold::MergedSection<mold::X86_64>::insert(mold::Context<mold::X86_64>&, std::basic_string_view<char, std::char_traits<char> >, unsigned long, long)
+ 11.07% 7.42% mold mold [.] mold::InputSection<mold::X86_64>::apply_reloc_nonalloc(mold::Context<mold::X86_64>&, unsigned char*)
+ 9.87% 0.19% mold libc.so.6 [.] __sched_yield
+ 9.53% 0.20% mold [kernel.kallsyms] [k] entry_SYSCALL_64_after_hwframe
+ 9.40% 0.32% mold [kernel.kallsyms] [k] do_syscall_64
+ 8.65% 0.16% mold [kernel.kallsyms] [k] x64_sys_call
+ 8.29% 1.23% mold libc.so.6 [.] __memcmp_evex_movbe
+ 7.96% 0.10% mold [kernel.kallsyms] [k] __x64_sys_sched_yield
+ 7.54% 0.92% mold [kernel.kallsyms] [k] do_sched_yield
+ 6.16% 0.14% mold [kernel.kallsyms] [k] schedule
+ 5.85% 0.71% mold [kernel.kallsyms] [k] __schedule
+ 5.62% 4.66% mold mold [.] mold::MergeableSection<mold::X86_64>::resolve_contents(mold::Context<mold::X86_64>&)
+ 4.54% 0.16% mold [kernel.kallsyms] [k] pick_next_task
+ 4.41% 4.35% mold mold [.] blake3_hash_many_avx512
+ 4.41% 1.19% mold [kernel.kallsyms] [k] pick_next_task_fair
+ 4.36% 0.00% mold [unknown] [k] 0x0000000000004000
+ 4.13% 2.51% mold libc.so.6 [.] __memchr_evex
+ 4.01% 2.08% mold mold [.] mold::MergeableSection<mold::X86_64>::split_contents(mold::Context<mold::X86_64>&)
+ 3.38% 2.60% mold mold [.] mold::InputSection<mold::X86_64>::record_undef_error(mold::Context<mold::X86_64>&, mold::ElfRel<mold::X86_64> const&)
+ 2.91% 1.37% mold [kernel.kallsyms] [k] update_curr
+ 2.48% 0.15% mold [kernel.kallsyms] [k] do_anonymous_page
+ 2.28% 0.00% mold [unknown] [.] 0x49544100ee86e305
+ 2.28% 0.00% mold mold [.] mold::ObjectFile<mold::X86_64>::~ObjectFile()
+ 2.17% 0.01% mold [kernel.kallsyms] [k] do_read_fault
+ 2.12% 0.20% mold [kernel.kallsyms] [k] filemap_map_pages
+ 1.98% 0.58% mold [kernel.kallsyms] [k] set_pte_range
+ 1.97% 1.00% mold mold [.] mold::ObjectFile<mold::X86_64>::initialize_sections(mold::Context<mold::X86_64>&)
+ 1.83% 1.07% mold mold [.] mold::Symbol<mold::X86_64>* mold::get_symbol<mold::X86_64>(mold::Context<mold::X86_64>&, std::basic_string_view<char, std::char_traits<char> >, std::basic_s
+ 1.79% 0.00% mold [kernel.kallsyms] [k] do_wp_page
+ 1.78% 0.01% mold [kernel.kallsyms] [k] wp_page_copy
+ 1.64% 1.36% mold mold [.] mold::ObjectFile<mold::X86_64>::resolve_symbols(mold::Context<mold::X86_64>&)
+ 1.52% 0.87% mold [kernel.kallsyms] [k] srso_alias_safe_ret
+ 1.47% 0.00% mold [kernel.kallsyms] [k] flush_tlb_mm_range
+ 1.45% 0.00% mold [kernel.kallsyms] [k] on_each_cpu_cond_mask
+ 1.45% 0.00% mold [kernel.kallsyms] [k] native_flush_tlb_multi
+ 1.44% 0.00% mold [kernel.kallsyms] [k] ptep_clear_flush
+ 1.41% 0.30% mold [kernel.kallsyms] [k] _raw_spin_lock
+ 1.41% 0.77% mold libc.so.6 [.] __strlen_evex
1.33% 1.27% mold mold [.] XXH_INLINE_XXH3_64bits
+ 1.23% 0.60% mold mold [.] tbb::detail::d2::concurrent_hash_map<std::basic_string_view<char, std::char_traits<char> >, mold::Symbol<mold::X86_64>, HashCmp, tbb::detail::d1::tbb_alloca
+ 1.18% 0.19% mold mold [.] tbb::detail::d2::concurrent_hash_map<std::basic_string_view<char, std::char_traits<char> >, mold::ComdatGroup, HashCmp, tbb::detail::d1::tbb_allocator<std::
+ 1.16% 0.02% mold [kernel.kallsyms] [k] vma_alloc_folio
+ 1.16% 0.02% mold [kernel.kallsyms] [k] alloc_anon_folio
+ 1.09% 0.86% mold mold [.] mold::ObjectFile<mold::X86_64>::reattach_section_pieces(mold::Context<mold::X86_64>&)
+ 1.06% 0.02% mold [kernel.kallsyms] [k] alloc_pages_mpol
+ 1.01% 0.92% mold [kernel.kallsyms] [k] __mod_node_page_state
+ 1.01% 0.00% mold [unknown] [.] 0xcccccccccccccccc
+ 0.92% 0.09% mold [kernel.kallsyms] [k] asm_sysvec_call_function
+ 0.91% 0.82% mold mold [.] mold::ObjectFile<mold::X86_64>::compute_symtab_size(mold::Context<mold::X86_64>&)
+ 0.91% 0.06% mold [kernel.kallsyms] [k] __alloc_pages
+ 0.90% 0.55% mold [kernel.kallsyms] [k] smp_call_function_many_cond
+ 0.89% 0.02% mold [kernel.kallsyms] [k] __do_fault
0.88% 0.76% mold [kernel.kallsyms] [k] srso_alias_return_thunk
+ 0.87% 0.80% mold mold [.] tbb::detail::d1::task* tbb::detail::r1::task_dispatcher::receive_or_steal_task<false, tbb::detail::r1::outermost_worker_waiter>(tbb::detail::r1::thread_data
+ 0.85% 0.08% mold [kernel.kallsyms] [k] folio_add_file_rmap_ptes
0.85% 0.42% mold [kernel.kallsyms] [k] ext4_dirty_folio
+ 0.83% 0.23% mold [kernel.kallsyms] [k] __lruvec_stat_mod_folio
+ 0.83% 0.04% mold [kernel.kallsyms] [k] filemap_faultNote that I built it not with RelWithDebInfo but with Debug .
marxin
commented
2 months ago Thanks, if filter out only the function related to mold, then the profile is very comparable to what I see. Interestingly, your CPU (which is faster) behaves quite differently, where LLD is much slower than on my machine and mold is faster.
Anyway, please update README.md where Clang has the following binary size: Clang 19 (1.56 GiB). I think it should be 4.06GiB, right?
DataM0del
commented
1 month ago The README page mentions the following benchmark:
Clang 19 (1.56 GiB) 42.07s 33.13s 5.20s 1.35s, but I cannot reproduce it on my AMD machine. First, am I right about the binary size (1.56 GiB) is measured with debug info? If so, did you use-DCMAKE_BUILD_TYPE=RelWithDebInfoor something else? Have you used any--compress-debug-sections=option?My numbers for
AMD Ryzen 9 7900X 12-Core Processorare:❯ bloaty ../../../../bin/clang-20 FILE SIZE VM SIZE -------------- -------------- 74.3% 3.31Gi 0.0% 0 .debug_info 9.4% 427Mi 0.0% 0 .debug_loclists 5.1% 231Mi 0.0% 0 .debug_str 4.8% 220Mi 0.0% 0 .debug_line 2.1% 95.8Mi 59.8% 95.8Mi .text 1.7% 76.4Mi 0.0% 0 .debug_rnglists 0.9% 41.3Mi 25.8% 41.3Mi .rodata 0.5% 23.6Mi 0.0% 0 .debug_abbrev 0.5% 23.5Mi 0.0% 0 .strtab 0.2% 9.72Mi 6.1% 9.72Mi .eh_frame 0.1% 5.44Mi 0.0% 0 .symtab 0.1% 4.49Mi 2.8% 4.49Mi .dynstr 0.1% 4.22Mi 2.6% 4.22Mi .data.rel.ro 0.1% 3.64Mi 0.0% 0 .debug_aranges 0.0% 1.30Mi 0.8% 1.30Mi .dynsym 0.0% 1.24Mi 0.8% 1.24Mi .eh_frame_hdr 0.0% 0 0.4% 715Ki .bss 0.0% 505Ki 0.3% 505Ki [24 Others] 0.0% 444Ki 0.3% 444Ki .hash 0.0% 404Ki 0.2% 404Ki .gnu.hash 0.0% 365Ki 0.0% 0 .debug_line_str 100.0% 4.45Gi 100.0% 160Mi TOTAL ❯ hyperfine ... -fuse-ld=mold Time (mean ± σ): 2.802 s ± 0.110 s [User: 0.009 s, System: 0.003 s] Range (min … max): 2.658 s … 2.999 s 10 runs ❯hyperfine ... -fuse-ld=lld Time (mean ± σ): 4.160 s ± 0.225 s [User: 40.475 s, System: 13.092 s] Range (min … max): 3.604 s … 4.428 s 10 runs ❯ ld.lld --version LLD 19.1.0 (compatible with GNU linkers) ❯ mold --version mold 2.33.0 (compatible with GNU ld)Both LLD and Mold are provided from openSUSE package (built with LTO). Compared to your numbers, LLD is 1.48x slower, while your numbers claim it's 3.85x. Can you please remeasure it?
bloaty ../../../../bin/clang-20
That's clang 20, not clang 19.
marxin
commented
1 month ago That's clang 20, not clang 19.
Yeah, but these two are very similar in size.
DataM0del
commented
1 month ago That's clang 20, not clang 19.
Yeah, but these two are very similar in size.
Yes, but the size doesn't really matter, it's like saying if I statically include 5,000 libraries and my executable is 5 MB but if I dynamically include those same libraries that the linker performance is the same, but the executable is only 3 MB. Statically linking something requires adding it into the binary, so the linker should be slower on static libraries. Dynamic linking, however, shouldn't need to link a shared object / DLL at compile time, the linker should only need to link the program and the static libraries that the program depends on. Also, you have changes made between clang 19 and clang 20, for example, it might require another library to statically link with, or replace a statically linked library with a dynamically linked library, or it may require more static libraries.
The README page mentions the following benchmark:
Clang 19 (1.56 GiB) 42.07s 33.13s 5.20s 1.35s, but I cannot reproduce it on my AMD machine. First, am I right about the binary size (1.56 GiB) is measured with debug info? If so, did you use-DCMAKE_BUILD_TYPE=RelWithDebInfoor something else? Have you used any--compress-debug-sections=option?My numbers for
AMD Ryzen 9 7900X 12-Core Processorare:Both LLD and Mold are provided from openSUSE package (built with LTO). Compared to your numbers, LLD is 1.48x slower, while your numbers claim it's 3.85x. Can you please remeasure it?