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Faster startup/smaller sysimg, excising Pkg (for now) #4
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@JeffBezanson My PR doesn't seem to be considered (maybe because it's not in JuliaLang's PR list, and I'm actually not sure why it appeared here, all my previous PRs didn't, I use the GitHub editor). Well, except you mentioned in total time would be higher, i.e. eaten up when you actually use functionality not loaded here/at startup. But I'm not convinced. Code in pkgimages is serialized to machine code too by now, and if/assuming the same code is compiled just elsewhere then should be as fast to load later. Besides some of the code might actually never be needed. I would like I think we should just merge this to master, and see if any benchmark actually shows slowdown. |
This commit improves SROA pass by extending the `unswitchtupleunion` optimization to handle the general parametric types, e.g.: ```julia julia> struct A{T} x::T end; julia> function foo(a1, a2, c) t = c ? A(a1) : A(a2) return getfield(t, :x) end; julia> only(Base.code_ircode(foo, (Int,Float64,Bool); optimize_until="SROA")) ``` > Before ``` 2 1 ─ goto #3 if not _4 │ 2 ─ %2 = %new(A{Int64}, _2)::A{Int64} │╻ A └── goto #4 │ 3 ─ %4 = %new(A{Float64}, _3)::A{Float64} │╻ A 4 ┄ %5 = φ (#2 => %2, #3 => %4)::Union{A{Float64}, A{Int64}} │ 3 │ %6 = Main.getfield(%5, :x)::Union{Float64, Int64} │ └── return %6 │ => Union{Float64, Int64} ``` > After ``` julia> only(Base.code_ircode(foo, (Int,Float64,Bool); optimize_until="SROA")) 2 1 ─ goto #3 if not _4 │ 2 ─ nothing::A{Int64} │╻ A └── goto #4 │ 3 ─ nothing::A{Float64} │╻ A 4 ┄ %8 = φ (#2 => _2, #3 => _3)::Union{Float64, Int64} │ │ nothing::Union{A{Float64}, A{Int64}} 3 │ %6 = %8::Union{Float64, Int64} │ └── return %6 │ => Union{Float64, Int64} ```
Rebase and extension of @alexfanqi's initial work on porting Julia to RISC-V. Requires LLVM 19. Tested on a VisionFive2, built with: ```make MARCH := rv64gc_zba_zbb MCPU := sifive-u74 USE_BINARYBUILDER:=0 DEPS_GIT = llvm override LLVM_VER=19.1.1 override LLVM_BRANCH=julia-release/19.x override LLVM_SHA1=julia-release/19.x ``` ```julia-repl ❯ ./julia _ _ _ _(_)_ | Documentation: https://docs.julialang.org (_) | (_) (_) | _ _ _| |_ __ _ | Type "?" for help, "]?" for Pkg help. | | | | | | |/ _` | | | | |_| | | | (_| | | Version 1.12.0-DEV.1374 (2024-10-14) _/ |\__'_|_|_|\__'_| | riscv/25092a3982* (fork: 1 commits, 0 days) |__/ | julia> versioninfo(; verbose=true) Julia Version 1.12.0-DEV.1374 Commit 25092a3* (2024-10-14 09:57 UTC) Platform Info: OS: Linux (riscv64-unknown-linux-gnu) uname: Linux 6.11.3-1-riscv64 #1 SMP Debian 6.11.3-1 (2024-10-10) riscv64 unknown CPU: unknown: speed user nice sys idle irq #1 1500 MHz 922 s 0 s 265 s 160953 s 0 s #2 1500 MHz 457 s 0 s 280 s 161521 s 0 s #3 1500 MHz 452 s 0 s 270 s 160911 s 0 s #4 1500 MHz 638 s 15 s 301 s 161340 s 0 s Memory: 7.760246276855469 GB (7474.08203125 MB free) Uptime: 16260.13 sec Load Avg: 0.25 0.23 0.1 WORD_SIZE: 64 LLVM: libLLVM-19.1.1 (ORCJIT, sifive-u74) Threads: 1 default, 0 interactive, 1 GC (on 4 virtual cores) Environment: HOME = /home/tim PATH = /home/tim/.local/bin:/usr/local/bin:/usr/bin:/bin:/usr/games TERM = xterm-256color julia> ccall(:jl_dump_host_cpu, Nothing, ()) CPU: sifive-u74 Features: +zbb,+d,+i,+f,+c,+a,+zba,+m,-zvbc,-zksed,-zvfhmin,-zbkc,-zkne,-zksh,-zfh,-zfhmin,-zknh,-v,-zihintpause,-zicboz,-zbs,-zvknha,-zvksed,-zfa,-ztso,-zbc,-zvknhb,-zihintntl,-zknd,-zvbb,-zbkx,-zkt,-zvkt,-zicond,-zvksh,-zvfh,-zvkg,-zvkb,-zbkb,-zvkned julia> @code_native debuginfo=:none 1+2. .text .attribute 4, 16 .attribute 5, "rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0_zifencei2p0_zmmul1p0_zba1p0_zbb1p0" .file "+" .globl "julia_+_3003" .p2align 1 .type "julia_+_3003",@function "julia_+_3003": addi sp, sp, -16 sd ra, 8(sp) sd s0, 0(sp) addi s0, sp, 16 fcvt.d.l fa5, a0 ld ra, 8(sp) ld s0, 0(sp) fadd.d fa0, fa5, fa0 addi sp, sp, 16 ret .Lfunc_end0: .size "julia_+_3003", .Lfunc_end0-"julia_+_3003" .type ".L+Core.Float64#3005",@object .section .data.rel.ro,"aw",@progbits .p2align 3, 0x0 ".L+Core.Float64#3005": .quad ".L+Core.Float64#3005.jit" .size ".L+Core.Float64#3005", 8 .set ".L+Core.Float64#3005.jit", 272467692544 .size ".L+Core.Float64#3005.jit", 8 .section ".note.GNU-stack","",@progbits ``` Lots of bugs guaranteed, but with this we at least have a functional build and REPL for further development by whoever is interested. Also requires Linux 6.4+, since the fallback processor detection used here relies on LLVM's `sys::getHostCPUFeatures`, which for RISC-V is implemented using hwprobe introduced in 6.4. We could probably add a fallback that parses `/proc/cpuinfo`, either by building a CPU database much like how we've done for AArch64, or by parsing the actual ISA string contained there. That would probably also be a good place to add support for profiles, which are supposedly the way forward to package RISC-V binaries. That can happen in follow-up PRs though. For now, on older kernels, use the `-C` arg to Julia to specify an ISA. Co-authored-by: Alex Fan <[email protected]>
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto JuliaLang#5 5 ── goto JuliaLang#6 6 ── goto JuliaLang#7 7 ── goto JuliaLang#8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto JuliaLang#9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto JuliaLang#10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible (JuliaLang#55990).
See: JuliaLang#50833 (comment)
It's 22% faster startup because the sysimage is 33% smaller.
With a minor breaking change it would be 30.2% faster and 37.5% smaller.