Author Topic: Zero a stack buffer (and probe it) (Read 41940 times)

jj2007 · « **on:** October 25, 2013, 07:31:54 PM »

Spin-off from MemStrategy:

AMD Athlon(tm) Dual Core Processor 4450B (SSE3) loop overhead is approx. 268/100 cycles 3778 kCycles for 100 * rep stosd 4905 kCycles for 100 * push 0 4890 kCycles for 100 * push edx 3343 kCycles for 100 * movups xmm0 3319 kCycles for 100 * movaps xmm0 3785 kCycles for 100 * rep stosd 4891 kCycles for 100 * push 0 4894 kCycles for 100 * push edx 3457 kCycles for 100 * movups xmm0 3319 kCycles for 100 * movaps xmm0 3785 kCycles for 100 * rep stosd 4891 kCycles for 100 * push 0 4896 kCycles for 100 * push edx 3342 kCycles for 100 * movups xmm0 3320 kCycles for 100 * movaps xmm0 18 bytes for rep stosd 17 bytes for push 0 16 bytes for push edx 22 bytes for movups xmm0 25 bytes for movaps xmm0

Siekmanski · « **Reply #1 on:** October 25, 2013, 07:58:50 PM »

Intel(R) Core(TM) i7-4930K CPU @ 3.40GHz (SSE4)
loop overhead is approx. 579/100 cycles

2700 kCycles for 100 * rep stosd
5467 kCycles for 100 * push 0
4888 kCycles for 100 * push edx
4266 kCycles for 100 * movups xmm0
1411 kCycles for 100 * movaps xmm0

2752 kCycles for 100 * rep stosd
4887 kCycles for 100 * push 0
5651 kCycles for 100 * push edx
4262 kCycles for 100 * movups xmm0
1030 kCycles for 100 * movaps xmm0

2699 kCycles for 100 * rep stosd
4892 kCycles for 100 * push 0
4888 kCycles for 100 * push edx
4263 kCycles for 100 * movups xmm0
1744 kCycles for 100 * movaps xmm0

18 bytes for rep stosd
17 bytes for push 0
16 bytes for push edx
22 bytes for movups xmm0
25 bytes for movaps xmm0

sinsi · « **Reply #2 on:** October 25, 2013, 08:40:15 PM »

Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz (SSE4)
loop overhead is approx. 310/100 cycles

2385 kCycles for 100 * rep stosd
4530 kCycles for 100 * push 0
4508 kCycles for 100 * push edx
3932 kCycles for 100 * movups xmm0
871 kCycles for 100 * movaps xmm0

TWell · « **Reply #3 on:** October 25, 2013, 09:05:27 PM »

AMD Athlon(tm) II X2 220 Processor (SSE3) 2.80 GHz
loop overhead is approx. 239/100 cycles

2621 kCycles for 100 * rep stosd
4891 kCycles for 100 * push 0
4895 kCycles for 100 * push edx
1666 kCycles for 100 * movups xmm0
1605 kCycles for 100 * movaps xmm0

dedndave · « **Reply #4 on:** October 25, 2013, 10:09:55 PM »

prescott w/htt

Intel(R) Pentium(R) 4 CPU 3.00GHz (SSE3)
loop overhead is approx. 248/100 cycles

4986    kCycles for 100 * rep stosd
4827    kCycles for 100 * push 0
4991    kCycles for 100 * push edx
6187    kCycles for 100 * movups xmm0
2767    kCycles for 100 * movaps xmm0

5023    kCycles for 100 * rep stosd
4857    kCycles for 100 * push 0
4935    kCycles for 100 * push edx
6207    kCycles for 100 * movups xmm0
2766    kCycles for 100 * movaps xmm0

5023    kCycles for 100 * rep stosd
4855    kCycles for 100 * push 0
4990    kCycles for 100 * push edx
6225    kCycles for 100 * movups xmm0
2765    kCycles for 100 * movaps xmm0

nidud · « **Reply #5 on:** October 25, 2013, 10:18:42 PM »

I cleaned up the rep stosd function a bit

Code: [Select]

	mov edx,edi
	lea edi,[esp-bufsize]
	mov ecx,bufsize/4
	xor eax,eax
	rep stosd
	mov edi,edx
	dec ebx

AMD Athlon(tm) II X2 245 Processor (SSE3)
loop overhead is approx. 239/100 cycles

2623 kCycles for 100 * rep stosd
4900 kCycles for 100 * push 0
4901 kCycles for 100 * push edx
1592 kCycles for 100 * movups xmm0
1597 kCycles for 100 * movaps xmm0
1955 kCycles for 100 * rep stosd

dedndave · « **Reply #6 on:** October 25, 2013, 10:34:57 PM »

prescott w/htt

Intel(R) Pentium(R) 4 CPU 3.00GHz (SSE3)
loop overhead is approx. 245/100 cycles

5107    kCycles for 100 * rep stosd
4844    kCycles for 100 * push 0
4902    kCycles for 100 * push edx
6153    kCycles for 100 * movups xmm0
2827    kCycles for 100 * movaps xmm0
2815    kCycles for 100 * rep stosd

5111    kCycles for 100 * rep stosd
4873    kCycles for 100 * push 0
4887    kCycles for 100 * push edx
6150    kCycles for 100 * movups xmm0
2795    kCycles for 100 * movaps xmm0
2782    kCycles for 100 * rep stosd

5053    kCycles for 100 * rep stosd
4892    kCycles for 100 * push 0
4850    kCycles for 100 * push edx
6179    kCycles for 100 * movups xmm0
2767    kCycles for 100 * movaps xmm0
2827    kCycles for 100 * rep stosd

Gunther · « **Reply #7 on:** October 25, 2013, 11:22:20 PM »

Jochen,

here are the results from an old Computer (located in an University laboratory). The other tests from my machine at home will come this evening.

Code: [Select]

AMD Athlon(tm) Dual Core Processor 5000B (SSE3)
loop overhead is approx. 239/100 cycles

3779    kCycles for 100 * rep stosd
4897    kCycles for 100 * push 0
4901    kCycles for 100 * push edx
3344    kCycles for 100 * movups xmm0
3347    kCycles for 100 * movaps xmm0

3774    kCycles for 100 * rep stosd
4897    kCycles for 100 * push 0
4899    kCycles for 100 * push edx
3343    kCycles for 100 * movups xmm0
3341    kCycles for 100 * movaps xmm0

3778    kCycles for 100 * rep stosd
4897    kCycles for 100 * push 0
4901    kCycles for 100 * push edx
3344    kCycles for 100 * movups xmm0
3331    kCycles for 100 * movaps xmm0

18      bytes for rep stosd
17      bytes for push 0
16      bytes for push edx
22      bytes for movups xmm0
25      bytes for movaps xmm0

--- ok ---

Gunther

nidud · « **Reply #8 on:** October 25, 2013, 11:35:41 PM »

Quote from: dedndave on October 25, 2013, 10:34:57 PM

prescott w/htt
Intel(R) Pentium(R) 4 CPU 3.00GHz (SSE3)
loop overhead is approx. 245/100 cycles

5107 kCycles for 100 * rep stosd
4844 kCycles for 100 * push 0
4902 kCycles for 100 * push edx
6153 kCycles for 100 * movups xmm0
2827 kCycles for 100 * movaps xmm0
2815 kCycles for 100 * rep stosd

manipulation of the (direction) flag again

shaves off some cycles on AMD but more on Intel

FORTRANS · « **Reply #9 on:** October 26, 2013, 12:05:07 AM »

Mobile Intel(R) Celeron(R) processor 600MHz (SSE2) loop overhead is approx. 211/100 cycles 7356 kCycles for 100 * rep stosd 4902 kCycles for 100 * push 0 4902 kCycles for 100 * push edx 3059 kCycles for 100 * movups xmm0 2312 kCycles for 100 * movaps xmm0 2207 kCycles for 100 * rep stosd 7358 kCycles for 100 * rep stosd 4905 kCycles for 100 * push 0 4897 kCycles for 100 * push edx 3064 kCycles for 100 * movups xmm0 2303 kCycles for 100 * movaps xmm0 2212 kCycles for 100 * rep stosd 7372 kCycles for 100 * rep stosd 4913 kCycles for 100 * push 0 4901 kCycles for 100 * push edx 3063 kCycles for 100 * movups xmm0 2303 kCycles for 100 * movaps xmm0 2214 kCycles for 100 * rep stosd 18 bytes for rep stosd 17 bytes for push 0 16 bytes for push edx 22 bytes for movups xmm0 25 bytes for movaps xmm0 17 bytes for rep stosd --- ok ---

jj2007 · « **Reply #10 on:** October 26, 2013, 12:52:01 AM »

Thanks to everybody :icon14:

Quote from: nidud on October 25, 2013, 10:18:42 PM

I cleaned up the rep stosd function a bit

I appreciate your good intentions, Nidud. Put it under TestA, just for fun ;)
(hint: look at this thread's title)

MichaelW · « **Reply #11 on:** October 26, 2013, 01:43:49 AM »

Northwood w/htt

Code: [Select]

Intel(R) Pentium(R) 4 CPU 3.00GHz (SSE2)
++18 of 20 tests valid, loop overhead is approx. 309/100 cycles

4910    kCycles for 100 * rep stosd
4902    kCycles for 100 * push 0
4904    kCycles for 100 * push edx
4904    kCycles for 100 * movups xmm0
2144    kCycles for 100 * movaps xmm0

4910    kCycles for 100 * rep stosd
5130    kCycles for 100 * push 0
4901    kCycles for 100 * push edx
4893    kCycles for 100 * movups xmm0
2140    kCycles for 100 * movaps xmm0

4911    kCycles for 100 * rep stosd
4909    kCycles for 100 * push 0
4903    kCycles for 100 * push edx
4895    kCycles for 100 * movups xmm0
2150    kCycles for 100 * movaps xmm0

18      bytes for rep stosd
17      bytes for push 0
16      bytes for push edx
22      bytes for movups xmm0
25      bytes for movaps xmm0

nidud · « **Reply #12 on:** October 26, 2013, 01:47:07 AM »

Quote from: jj2007 on October 26, 2013, 12:52:01 AM

Put it under TestA, just for fun ;)

the intention should at best be educational :P

having both of them will illustrate the penalty of manipulating the flags on different CPU's

dedndave · « **Reply #13 on:** October 26, 2013, 01:50:10 AM »

i try to avoid STD's :lol:

in fact, i have gotten to where i don't use them at all
if i have to move things in that direction, i write a discrete loop

in this case, you could probe, then clear, one page at a time
something like this...

Code: [Select]

    ASSUME  FS:Nothing

    mov     edx,esp
    mov     fs:[700h],edi
    xor     eax,eax
    sub     edx,<NumberOfBytesRequiredPlus3Mod4>
    .repeat
        push    eax
        mov     ecx,esp
        mov     esp,fs:[8]
        sub     ecx,esp
        shr     ecx,2
        .if !ZERO
            mov     edi,esp
            rep     stosd
        .endif
    .until edx>=esp
    mov     edi,fs:[700h]
    mov     esp,edx

    ASSUME  FS:ERROR

dedndave · « **Reply #14 on:** October 26, 2013, 02:28:02 AM »

this is a simpler version...

Code: [Select]

    ASSUME  FS:Nothing

    mov     edx,esp
    mov     ecx,esp
    sub     edx,<NumberOfBytesRequiredPlus3Mod4>
    .repeat
        push    eax
        mov     esp,fs:[8]
    .until edx>=esp
    sub     ecx,edx
    xchg    edx,edi
    shr     ecx,2
    xor     eax,eax
    mov     esp,edi
    rep     stosd
    mov     edi,edx

    ASSUME  FS:ERROR

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Author Topic: Zero a stack buffer (and probe it) (Read 41940 times)

jj2007

Zero a stack buffer (and probe it)

Siekmanski

Re: Zero a stack buffer (and probe it)

sinsi

Re: Zero a stack buffer (and probe it)

TWell

Re: Zero a stack buffer (and probe it)

dedndave

Re: Zero a stack buffer (and probe it)

nidud

Re: Zero a stack buffer (and probe it)

dedndave

Re: Zero a stack buffer (and probe it)

Gunther

Re: Zero a stack buffer (and probe it)

nidud

Re: Zero a stack buffer (and probe it)

FORTRANS

Re: Zero a stack buffer (and probe it)

jj2007

Re: Zero a stack buffer (and probe it)

MichaelW

Re: Zero a stack buffer (and probe it)

nidud

Re: Zero a stack buffer (and probe it)

dedndave

Re: Zero a stack buffer (and probe it)

dedndave

Re: Zero a stack buffer (and probe it)