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Faster startup/smaller sysimg, excising Pkg (for now) #4

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@PallHaraldsson PallHaraldsson commented Aug 9, 2023

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.

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PallHaraldsson commented Aug 25, 2023

@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 using to work in parallel (at some point), I can at least see it conceivable that (maybe just one) using would be done in parallel with other code running.

I think we should just merge this to master, and see if any benchmark actually shows slowdown.

ViralBShah pushed a commit that referenced this pull request Nov 2, 2023
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}
```
inkydragon pushed a commit that referenced this pull request Jan 15, 2025
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]>
inkydragon pushed a commit that referenced this pull request Jan 15, 2025
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).
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