Code to test performance of new pure Julia reverse(str::UTF8String), along with test results from my MacBook Pro

results-0818

julia> dotest(1000000)
Length of string: 0
ASCII reverse:      0.056237 seconds (2.00 M allocations: 91.553 MB, 11.00% gc time)
UTF-8 oldreverse:   0.037658 seconds (2.00 M allocations: 91.553 MB, 7.40% gc time)
UTF-8 newreverse:   0.003620 seconds
UTF-16 reverse:     0.046076 seconds (2.00 M allocations: 91.553 MB, 8.44% gc time)
UTF-32 reverse:     0.054243 seconds (2.00 M allocations: 91.553 MB, 6.92% gc time)

  0.142451 seconds (6.00 M allocations: 274.666 MB, 7.32% gc time)
Length of string: 1
ASCII reverse:      0.042259 seconds (2.00 M allocations: 91.553 MB, 7.25% gc time)
ASCII values:
UTF-8 oldreverse:   0.041105 seconds (2.00 M allocations: 91.553 MB, 9.24% gc time)
UTF-8 newreverse:   0.003491 seconds
UTF-16 reverse:     0.044414 seconds (2.00 M allocations: 91.553 MB, 6.95% gc time)
UTF-32 reverse:     0.048348 seconds (2.00 M allocations: 91.553 MB, 6.17% gc time)

Latin1 values:
UTF-8 oldreverse:   0.041937 seconds (2.00 M allocations: 91.553 MB, 9.69% gc time)
UTF-8 newreverse:   0.046335 seconds (2.00 M allocations: 91.553 MB, 7.21% gc time)
UTF-16 reverse:     0.045165 seconds (2.00 M allocations: 91.553 MB, 6.76% gc time)
UTF-32 reverse:     0.050539 seconds (2.00 M allocations: 91.553 MB, 6.23% gc time)

UCS2 values:
UTF-8 oldreverse:   0.039621 seconds (2.00 M allocations: 91.553 MB, 7.60% gc time)
UTF-8 newreverse:   0.045446 seconds (2.00 M allocations: 91.553 MB, 8.49% gc time)
UTF-16 reverse:     0.045310 seconds (2.00 M allocations: 91.553 MB, 6.72% gc time)
UTF-32 reverse:     0.047398 seconds (2.00 M allocations: 91.553 MB, 7.43% gc time)

Chars > 0xffff:
UTF-8 oldreverse:   0.045028 seconds (2.00 M allocations: 91.553 MB, 7.92% gc time)
UTF-8 newreverse:   0.043877 seconds (2.00 M allocations: 91.553 MB, 7.21% gc time)
UTF-16 reverse:     0.047826 seconds (2.00 M allocations: 91.553 MB, 6.64% gc time)
UTF-32 reverse:     0.056674 seconds (2.00 M allocations: 91.553 MB, 7.96% gc time)

Length of string: 4
ASCII reverse:      0.046714 seconds (2.00 M allocations: 91.553 MB, 6.93% gc time)
ASCII values:
UTF-8 oldreverse:   0.052762 seconds (2.00 M allocations: 91.553 MB, 7.88% gc time)
UTF-8 newreverse:   0.043381 seconds (2.00 M allocations: 91.553 MB, 7.98% gc time)
UTF-16 reverse:     0.046619 seconds (2.00 M allocations: 91.553 MB, 6.97% gc time)
UTF-32 reverse:     0.067789 seconds (2.00 M allocations: 106.812 MB, 13.26% gc time)

Latin1 values:
UTF-8 oldreverse:   0.047569 seconds (2.00 M allocations: 91.553 MB, 9.38% gc time)
UTF-8 newreverse:   0.046444 seconds (2.00 M allocations: 91.553 MB, 9.37% gc time)
UTF-16 reverse:     0.051302 seconds (2.00 M allocations: 91.553 MB, 7.80% gc time)
UTF-32 reverse:     0.060555 seconds (2.00 M allocations: 106.812 MB, 14.66% gc time)

UCS2 values:
UTF-8 oldreverse:   0.046441 seconds (2.00 M allocations: 91.553 MB, 8.19% gc time)
UTF-8 newreverse:   0.051044 seconds (2.00 M allocations: 91.553 MB, 7.14% gc time)
UTF-16 reverse:     0.047345 seconds (2.00 M allocations: 91.553 MB, 7.17% gc time)
UTF-32 reverse:     0.062245 seconds (2.00 M allocations: 106.812 MB, 13.33% gc time)

Chars > 0xffff:
UTF-8 oldreverse:   0.047050 seconds (2.00 M allocations: 91.553 MB, 8.19% gc time)
UTF-8 newreverse:   0.046330 seconds (2.00 M allocations: 91.553 MB, 9.19% gc time)
UTF-16 reverse:     0.051295 seconds (2.00 M allocations: 91.553 MB, 6.55% gc time)
UTF-32 reverse:     0.060346 seconds (2.00 M allocations: 106.812 MB, 13.86% gc time)

Length of string: 8
ASCII reverse:      0.053933 seconds (2.00 M allocations: 91.553 MB, 7.04% gc time)
ASCII values:
UTF-8 oldreverse:   0.050015 seconds (2.00 M allocations: 91.553 MB, 6.98% gc time)
UTF-8 newreverse:   0.044817 seconds (2.00 M allocations: 91.553 MB, 7.01% gc time)
UTF-16 reverse:     0.055804 seconds (2.00 M allocations: 106.812 MB, 14.63% gc time)
UTF-32 reverse:     0.087160 seconds (2.00 M allocations: 122.071 MB, 23.70% gc time)

Latin1 values:
UTF-8 oldreverse:   0.053177 seconds (2.00 M allocations: 91.553 MB, 7.72% gc time)
UTF-8 newreverse:   0.049747 seconds (2.00 M allocations: 91.553 MB, 6.83% gc time)
UTF-16 reverse:     0.059836 seconds (2.00 M allocations: 106.812 MB, 15.06% gc time)
UTF-32 reverse:     0.075300 seconds (2.00 M allocations: 122.071 MB, 22.69% gc time)

UCS2 values:
UTF-8 oldreverse:   0.047666 seconds (2.00 M allocations: 91.553 MB, 13.84% gc time)
UTF-8 newreverse:   0.054100 seconds (2.00 M allocations: 91.553 MB, 6.70% gc time)
UTF-16 reverse:     0.057785 seconds (2.00 M allocations: 106.812 MB, 14.92% gc time)
UTF-32 reverse:     0.078539 seconds (2.00 M allocations: 122.071 MB, 21.44% gc time)

Chars > 0xffff:
UTF-8 oldreverse:   0.047186 seconds (2.00 M allocations: 91.553 MB, 11.27% gc time)
UTF-8 newreverse:   0.045796 seconds (2.00 M allocations: 91.553 MB, 8.85% gc time)
UTF-16 reverse:     0.056153 seconds (2.00 M allocations: 106.812 MB, 14.88% gc time)
UTF-32 reverse:     0.071291 seconds (2.00 M allocations: 122.071 MB, 22.02% gc time)

Length of string: 16
ASCII reverse:      0.060178 seconds (2.00 M allocations: 106.812 MB, 15.36% gc time)
ASCII values:
UTF-8 oldreverse:   0.059139 seconds (2.00 M allocations: 106.812 MB, 13.68% gc time)
UTF-8 newreverse:   0.064110 seconds (2.00 M allocations: 106.812 MB, 14.58% gc time)
UTF-16 reverse:     0.082799 seconds (2.00 M allocations: 122.071 MB, 24.45% gc time)
UTF-32 reverse:     0.091677 seconds (2.00 M allocations: 152.588 MB, 27.74% gc time)

Latin1 values:
UTF-8 oldreverse:   0.066855 seconds (2.00 M allocations: 106.812 MB, 16.39% gc time)
UTF-8 newreverse:   0.066047 seconds (2.00 M allocations: 106.812 MB, 13.95% gc time)
UTF-16 reverse:     0.083560 seconds (2.00 M allocations: 122.071 MB, 24.83% gc time)
UTF-32 reverse:     0.089040 seconds (2.00 M allocations: 152.588 MB, 29.19% gc time)

UCS2 values:
UTF-8 oldreverse:   0.059305 seconds (2.00 M allocations: 106.812 MB, 14.27% gc time)
UTF-8 newreverse:   0.061206 seconds (2.00 M allocations: 106.812 MB, 10.40% gc time)
UTF-16 reverse:     0.088623 seconds (2.00 M allocations: 122.071 MB, 23.10% gc time)
UTF-32 reverse:     0.089503 seconds (2.00 M allocations: 152.588 MB, 30.00% gc time)

Chars > 0xffff:
UTF-8 oldreverse:   0.068810 seconds (2.00 M allocations: 106.812 MB, 17.35% gc time)
UTF-8 newreverse:   0.059569 seconds (2.00 M allocations: 106.812 MB, 14.30% gc time)
UTF-16 reverse:     0.081272 seconds (2.00 M allocations: 122.071 MB, 19.47% gc time)
UTF-32 reverse:     0.088320 seconds (2.00 M allocations: 152.588 MB, 26.54% gc time)

Length of string: 64
ASCII reverse:      0.128005 seconds (2.00 M allocations: 152.588 MB, 22.81% gc time)
ASCII values:
UTF-8 oldreverse:   0.128985 seconds (2.00 M allocations: 152.588 MB, 21.58% gc time)
UTF-8 newreverse:   0.142336 seconds (2.00 M allocations: 152.588 MB, 21.13% gc time)
UTF-16 reverse:     0.152780 seconds (2.00 M allocations: 213.623 MB, 26.39% gc time)
UTF-32 reverse:     0.170482 seconds (2.00 M allocations: 396.729 MB, 36.47% gc time)

Latin1 values:
UTF-8 oldreverse:   0.146011 seconds (2.00 M allocations: 152.588 MB, 19.97% gc time)
UTF-8 newreverse:   0.146322 seconds (2.00 M allocations: 152.588 MB, 19.15% gc time)
UTF-16 reverse:     0.146836 seconds (2.00 M allocations: 213.623 MB, 27.09% gc time)
UTF-32 reverse:     0.167517 seconds (2.00 M allocations: 396.729 MB, 35.38% gc time)

UCS2 values:
UTF-8 oldreverse:   0.133692 seconds (2.00 M allocations: 152.588 MB, 19.01% gc time)
UTF-8 newreverse:   0.141955 seconds (2.00 M allocations: 152.588 MB, 20.95% gc time)
UTF-16 reverse:     0.150047 seconds (2.00 M allocations: 213.623 MB, 28.45% gc time)
UTF-32 reverse:     0.169460 seconds (2.00 M allocations: 396.729 MB, 36.12% gc time)

Chars > 0xffff:
UTF-8 oldreverse:   0.144327 seconds (2.00 M allocations: 152.588 MB, 21.39% gc time)
UTF-8 newreverse:   0.168502 seconds (2.00 M allocations: 152.588 MB, 17.93% gc time)
UTF-16 reverse:     0.164903 seconds (2.00 M allocations: 213.623 MB, 27.13% gc time)
UTF-32 reverse:     0.192607 seconds (2.00 M allocations: 396.729 MB, 36.02% gc time)

Length of string: 256
ASCII reverse:      0.340366 seconds (2.00 M allocations: 396.729 MB, 22.01% gc time)
ASCII values:
UTF-8 oldreverse:   0.367536 seconds (2.00 M allocations: 396.729 MB, 21.02% gc time)
UTF-8 newreverse:   0.346424 seconds (2.00 M allocations: 396.729 MB, 21.23% gc time)
UTF-16 reverse:     0.415075 seconds (2.00 M allocations: 610.352 MB, 27.36% gc time)
UTF-32 reverse:     0.436749 seconds (2.00 M allocations: 1.103 GB, 39.53% gc time)

Latin1 values:
UTF-8 oldreverse:   0.426764 seconds (2.00 M allocations: 396.729 MB, 18.80% gc time)
UTF-8 newreverse:   0.424360 seconds (2.00 M allocations: 396.729 MB, 17.64% gc time)
UTF-16 reverse:     0.432054 seconds (2.00 M allocations: 610.352 MB, 27.65% gc time)
UTF-32 reverse:     0.405953 seconds (2.00 M allocations: 1.103 GB, 39.80% gc time)

UCS2 values:
UTF-8 oldreverse:   0.370457 seconds (2.00 M allocations: 396.729 MB, 21.41% gc time)
UTF-8 newreverse:   0.436571 seconds (2.00 M allocations: 396.729 MB, 17.26% gc time)
UTF-16 reverse:     0.423437 seconds (2.00 M allocations: 610.352 MB, 27.63% gc time)
UTF-32 reverse:     0.425747 seconds (2.00 M allocations: 1.103 GB, 39.11% gc time)

Chars > 0xffff:
UTF-8 oldreverse:   0.375635 seconds (2.00 M allocations: 396.729 MB, 19.48% gc time)
UTF-8 newreverse:   0.527642 seconds (2.00 M allocations: 396.729 MB, 14.54% gc time)
UTF-16 reverse:     0.454972 seconds (2.00 M allocations: 656.129 MB, 27.24% gc time)
UTF-32 reverse:     0.418369 seconds (2.00 M allocations: 1.103 GB, 40.37% gc time)

Length of string: 1024
ASCII reverse:      1.137994 seconds (2.00 M allocations: 1.103 GB, 18.84% gc time)
ASCII values:
UTF-8 oldreverse:   1.197267 seconds (2.00 M allocations: 1.103 GB, 17.88% gc time)
UTF-8 newreverse:   1.196598 seconds (2.00 M allocations: 1.103 GB, 18.38% gc time)
UTF-16 reverse:     1.413917 seconds (2.00 M allocations: 2.012 GB, 20.07% gc time)
UTF-32 reverse:     1.198975 seconds (2.00 M allocations: 3.919 GB, 27.13% gc time)

Latin1 values:
UTF-8 oldreverse:   1.390881 seconds (2.00 M allocations: 1.103 GB, 15.10% gc time)
UTF-8 newreverse:   1.545459 seconds (2.00 M allocations: 1.103 GB, 14.62% gc time)
UTF-16 reverse:     1.518551 seconds (2.00 M allocations: 2.012 GB, 21.30% gc time)
UTF-32 reverse:     1.242489 seconds (2.00 M allocations: 3.919 GB, 27.60% gc time)

UCS2 values:
UTF-8 oldreverse:   1.248608 seconds (2.00 M allocations: 1.177 GB, 18.47% gc time)
UTF-8 newreverse:   1.538900 seconds (2.00 M allocations: 1.177 GB, 14.86% gc time)
UTF-16 reverse:     1.453261 seconds (2.00 M allocations: 2.012 GB, 21.23% gc time)
UTF-32 reverse:     1.282385 seconds (2.00 M allocations: 3.919 GB, 27.68% gc time)

Chars > 0xffff:
UTF-8 oldreverse:   1.299516 seconds (2.00 M allocations: 1.281 GB, 18.30% gc time)
UTF-8 newreverse:   2.049694 seconds (2.00 M allocations: 1.281 GB, 11.97% gc time)
UTF-16 reverse:     1.456468 seconds (2.00 M allocations: 2.131 GB, 20.06% gc time)
UTF-32 reverse:     1.260085 seconds (2.00 M allocations: 4.157 GB, 26.16% gc time)

Length of string: 4096
ASCII reverse:      4.105720 seconds (2.00 M allocations: 3.919 GB, 12.61% gc time)
ASCII values:
UTF-8 oldreverse:   4.276641 seconds (2.00 M allocations: 3.919 GB, 12.21% gc time)
UTF-8 newreverse:   4.267139 seconds (2.00 M allocations: 3.919 GB, 12.28% gc time)
UTF-16 reverse:     4.728655 seconds (2.00 M allocations: 7.734 GB, 14.42% gc time)
UTF-32 reverse:     4.057931 seconds (3.00 M allocations: 15.348 GB, 24.56% gc time)

Latin1 values:
UTF-8 oldreverse:   5.540127 seconds (2.00 M allocations: 4.157 GB, 9.46% gc time)
UTF-8 newreverse:   5.604333 seconds (2.00 M allocations: 4.157 GB, 9.42% gc time)
UTF-16 reverse:     4.815122 seconds (2.00 M allocations: 7.734 GB, 14.70% gc time)
UTF-32 reverse:     4.165398 seconds (3.00 M allocations: 15.348 GB, 24.82% gc time)

UCS2 values:
UTF-8 oldreverse:   4.628135 seconds (2.00 M allocations: 4.396 GB, 11.86% gc time)
UTF-8 newreverse:   5.866495 seconds (2.00 M allocations: 4.396 GB, 9.44% gc time)
UTF-16 reverse:     4.537087 seconds (2.00 M allocations: 7.734 GB, 13.68% gc time)
UTF-32 reverse:     3.897756 seconds (3.00 M allocations: 15.348 GB, 24.05% gc time)

Chars > 0xffff:
UTF-8 oldreverse:   4.716892 seconds (2.00 M allocations: 4.634 GB, 12.02% gc time)
UTF-8 newreverse:   7.894531 seconds (2.00 M allocations: 4.634 GB, 7.21% gc time)
UTF-16 reverse:     5.014368 seconds (2.00 M allocations: 8.211 GB, 14.32% gc time)
UTF-32 reverse:     4.348015 seconds (3.00 M allocations: 16.302 GB, 24.73% gc time)

Length of string: 16384
ASCII reverse:     15.248985 seconds (3.00 M allocations: 15.348 GB, 10.29% gc time)
ASCII values:
UTF-8 oldreverse:  16.403243 seconds (3.00 M allocations: 15.348 GB, 10.08% gc time)
UTF-8 newreverse:  16.085859 seconds (3.00 M allocations: 15.348 GB, 9.38% gc time)
UTF-16 reverse:    16.989447 seconds (3.00 M allocations: 30.607 GB, 11.32% gc time)
UTF-32 reverse:    17.613437 seconds (3.00 M allocations: 61.125 GB, 22.62% gc time)

Latin1 values:
UTF-8 oldreverse:  22.172378 seconds (3.00 M allocations: 16.302 GB, 7.29% gc time)
UTF-8 newreverse:  21.677226 seconds (3.00 M allocations: 16.302 GB, 7.49% gc time)
UTF-16 reverse:    18.306207 seconds (3.00 M allocations: 30.607 GB, 12.79% gc time)
UTF-32 reverse:    16.821477 seconds (3.00 M allocations: 61.125 GB, 22.92% gc time)

UCS2 values:
UTF-8 oldreverse:  17.363041 seconds (3.00 M allocations: 17.256 GB, 9.44% gc time)
UTF-8 newreverse:  22.434713 seconds (3.00 M allocations: 17.256 GB, 7.24% gc time)
UTF-16 reverse:    17.906505 seconds (3.00 M allocations: 30.607 GB, 12.29% gc time)
UTF-32 reverse:    17.722014 seconds (3.00 M allocations: 61.125 GB, 23.17% gc time)

Chars > 0xffff:
UTF-8 oldreverse:  17.909246 seconds (3.00 M allocations: 18.209 GB, 8.86% gc time)
UTF-8 newreverse:  29.814591 seconds (3.00 M allocations: 18.209 GB, 5.34% gc time)
UTF-16 reverse:    17.806809 seconds (3.00 M allocations: 32.514 GB, 11.04% gc time)
UTF-32 reverse:    18.531684 seconds (3.00 M allocations: 64.939 GB, 23.12% gc time)

revperf.jl

VERSION < v"0.4-" && (typealias AbstractString String)

@noinline throw_uni_error(msg, pos, ch) = throw(UnicodeError(msg, pos, ch))

function newreverse(s::UTF8String)
    dat = s.data
    n = length(dat)
    n <= 1 && return s
    buf = Vector{UInt8}(n)
    out = n
    pos = 1
    @inbounds while out > 0
        ch = dat[pos]
        if ch > 0xdf
            if ch < 0xf0
                (out -= 3) < 0 && throw_uni_error(Base.UTF_ERR_SHORT, pos, ch)
                buf[out + 1], buf[out + 2], buf[out + 3] = ch, dat[pos + 1], dat[pos + 2]
                pos += 3
            else
                (out -= 4) < 0 && throw_uni_error(Base.UTF_ERR_SHORT, pos, ch)
                buf[out+1], buf[out+2], buf[out+3], buf[out+4] = ch, dat[pos+1], dat[pos+2], dat[pos+3]
                pos += 4
            end
        elseif ch > 0x7f
            (out -= 2) < 0 && throw_uni_error(Base.UTF_ERR_SHORT, pos, ch)
            buf[out + 1], buf[out + 2] = ch, dat[pos + 1]
            pos += 2
        else
            buf[out] = ch
            out -= 1
            pos += 1
        end
    end
    UTF8String(buf)
end

function oldreverse(s::UTF8String)
    out = similar(s.data)
    if ccall(:u8_reverse, Cint, (Ptr{UInt8}, Ptr{UInt8}, Csize_t),
             out, s.data, length(out)) == 1
        throw(UnicodeError(Base.UTF_ERR_INVALID_8,0,0))
    end
    UTF8String(out)
end

function tst{T <: AbstractString}(str::T, max::Int)
    local out
    for i=1:max
	out = reverse(str)
    end
    out
end

function tstold{T <: AbstractString}(str::T, max::Int)
    local out
    for i=1:max
	out = oldreverse(str)
    end
    out
end

function tstnew{T <: AbstractString}(str::T, max::Int)
    local out
    for i=1:max
	out = newreverse(str)
    end
    out
end

function tstrev(n::Int, strUTF8::UTF8String)
    print("UTF-8 oldreverse: ")
    @time tstold(strUTF8,n)
    print("UTF-8 newreverse: ")
    @time tstnew(strUTF8,n)
    print("UTF-16 reverse:   ")
    @time tst(utf16(strUTF8),n)
    print("UTF-32 reverse:   ")
    @time tst(utf32(strUTF8),n)
    println()
    ""
end

function tstreverse(n,strAscii,strA_UTF8,strL_UTF8,str3_UTF8,str4_UTF8)
    println("Length of string: ",length(strAscii))
    print("ASCII reverse:    ")
    @time tst(strAscii,n)
    println("ASCII values:")
    tstrev(n,strA_UTF8)
    println("Latin1 values:")
    tstrev(n,strL_UTF8)
    println("UCS2 values:")
    tstrev(n,str3_UTF8)
    println("Chars > 0xffff:")
    tstrev(n,str4_UTF8)
end

function dotest(n)
    strA = "a"
    strL = "\uff"
    str3 = "\u7fff"
    str4 = "\u7ffff"
    ascstr = "bcdefghijklmnop"

    println("Length of string: 0")
    print("ASCII reverse:    ")
    @time tst("",n)
    @time tstrev(n, utf8(""))

    for extra in ("", ascstr[1:3], ascstr[1:7], ascstr)
        tstreverse(n,strA*extra,utf8(strA*extra),strL*extra,str3*extra,str4*extra)
    end

    strA *= ascstr
    strL *= ascstr
    str3 *= ascstr
    str4 *= ascstr

    for i=1:5
	strA ^= 4
	strL ^= 4
	str3 ^= 4
	str4 ^= 4
	tstreverse(n,strA,utf8(strA),strL,str3,str4)
    end
end
""