AVX-512 - 使用英特尔 SDE 调试应用程序不工作
AVX-512 - Debugging application with Intel SDE not working
我正在尝试使用 Intel® Software Development Emulator but it doesn't work as desired after setting a breakpoint. I followed this blog post: Debugging Emulated Code on Linux*
在模拟的 CPU 上调试 AVX-512 指令
在window #1:
~$ g++ -g -O0 -mavx512f main.cpp -o main # compile main.cpp file
~$ sde -debug -- ./main # enable debugging
Application stopped until continued from debugger.
Start GDB, then issue this command at the (gdb) prompt:
target remote :54105
在window#2
# run debugger
~$ gdb ./main
GNU gdb (Ubuntu 9.2-0ubuntu1~20.04) 9.2
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from ./main...
# set target "target remote :portnumber"
(gdb) target remote :54105
Remote debugging using :54105
warning: remote target does not support file transfer, attempting to access files from local filesystem.
Reading symbols from /lib64/ld-linux-x86-64.so.2...
(No debugging symbols found in /lib64/ld-linux-x86-64.so.2)
0x00007fa7bbbcc100 in ?? () from /lib64/ld-linux-x86-64.so.2
# suspend program at main function
(gdb) break main
Breakpoint 1 at 0x2c9c: file /home/borrow/source/repos/se-test/main.cpp, line 165.
# start program execution from the beginning of the program
(gdb) run
The "remote" target does not support "run". Try "help target" or
"continue".
# step to next line of code
(gdb) step
Cannot find bounds of current function
# continue executing until next break point
(gdb) c
Continuing.
warning: Probes-based dynamic linker interface failed.
Reverting to original interface.
[Inferior 1 (Remote target) exited normally]
在window#2：如你所见
gdb run 应该 运行 一个程序，但它不起作用。 gdb c 也应该 运行 直到下一个断点但执行程序并终止。此命令给我以下警告消息：
warning: Probes-based dynamic linker interface failed.
在 window #1 中：程序 运行 结束（没有停止）。
程序代码如下所示：
// main.cpp
#include <immintrin.h>
const int N=64;
int64_t srcA[N] = {0};
int64_t srcB[N] = {0};
int64_t dst[N] = {0};
void foo()
{
__m512i result,B,C;
for ( int i=0; i<N; i+=8 ){
B = _mm512_loadu_si512(&srcA[i]);
C = _mm512_loadu_si512(&srcB[i]);
result = _mm512_add_epi64(B,C);
_mm512_storeu_si512(&dst[i], result);
}
}
int main() {
...
foo();
...
}
我尝试 运行使用 gdb 在没有 SDE 模拟器的情况下使用 AVX2 代码，它成功了。首先，我在带有 SDE 的模拟 CPU 上启动它，它失败了。我该如何解决这个问题？
PIE 可执行文件似乎已损坏
（在 Arch GNU/Linux 上使用 GCC 10.2、GDB 10.1、SDE 8.33 确认。）
使用 g++ -O2 -fno-pie -no-pie -g -march=skylake-avx512 构建，一切正常。 （我不得不 运行 gdb ./a.out 而不是裸 GDB；否则即使连接到远程也找不到正确的文件。）
$ g++ -O2 -march=skylake-avx512 -no-pie -fno-pie -g avx512.cpp
$ /opt/sde-external-8.33.0-2019-02-07-lin/sde64 -debug -- ./a.out
Application stopped until continued from debugger.
Start GDB, then issue this command at the (gdb) prompt:
target remote :59783
然后在另一个终端选项卡中
$ gdb ./a.out
...
(gdb) target remote :59783
warning: remote target does not support file transfer, attempting to access files from local filesystem.
Reading symbols from /lib64/ld-linux-x86-64.so.2...
(No debugging symbols found in /lib64/ld-linux-x86-64.so.2)
0x00007f4f7033b090 in _start () from /lib64/ld-linux-x86-64.so.2
(gdb) b main
Breakpoint 1 at 0x401050: file avx512.cpp, line 29.
(gdb) b foo
Breakpoint 2 at 0x401190: file avx512.cpp, line 14.
(gdb) c
Continuing.
Breakpoint 1, main () at avx512.cpp:23
(gdb) layout asm
(copy-paste of some of the disassembly window)
│B+ 0x401120 <_Z3foov> xor eax,eax
│ 0x401122 <_Z3foov+2> nop WORD PTR [rax+rax*1+0x0]
│ >0x401128 <_Z3foov+8> vmovdqu64 zmm1,ZMMWORD PTR [rax+0x404260]
│ 0x401132 <_Z3foov+18> add rax,0x40
│ 0x401136 <_Z3foov+22> vpaddq zmm0,zmm1,ZMMWORD PTR [rax+0x404420]
│ 0x401140 <_Z3foov+32> vmovdqu64 ZMMWORD PTR [rax+0x404020],zmm0
│ 0x40114a <_Z3foov+42> cmp rax,0x200
│ 0x401150 <_Z3foov+48> jne 0x401128 <_Z3foov+8>
│ 0x401152 <_Z3foov+50> vzeroupper
│ 0x401155 <_Z3foov+53> ret
(gdb) layout src
asm 级和源代码级调试都工作正常，在使用 stepi（又名 si）时进入 avx512fintrin.h 中的内在“功能”等。
在连接到远程时不单独指定文件名：
$ gdb
(gdb) target remote :46879
Remote debugging using :46879 warning: No executable has been specified and target does not support determining executable automatically. Try using the "file" command.
0x00007f0f85830090 in ?? ()
(gdb)
（IDK 如果我的 .gdbinit 包括 layout reg，全屏终端 TUI 模式很重要。它工作时很好，但有点错误。）
或者作为 PIE 可执行文件的超级 hacky 解决方法，我还能够在 main 的顶部放置一个延迟循环，让您有机会在 SDE 完成执行您的之前附加然后控制-C程序。
然后我可以设置断点并开始单步执行。 （大概 sleep 或 read 系统调用会起作用）。源代码级调试似乎仍然失败，但我能够使用 layout reg 调试 asm。在附加并点击 control-C 后，我使用 set $rip = ... 和复制粘贴的地址来退出 _mm_pause() 循环。
我正在尝试使用 Intel® Software Development Emulator but it doesn't work as desired after setting a breakpoint. I followed this blog post: Debugging Emulated Code on Linux*
在模拟的 CPU 上调试 AVX-512 指令在window #1:
~$ g++ -g -O0 -mavx512f main.cpp -o main # compile main.cpp file
~$ sde -debug -- ./main # enable debugging
Application stopped until continued from debugger.
Start GDB, then issue this command at the (gdb) prompt:
target remote :54105
在window#2
# run debugger
~$ gdb ./main
GNU gdb (Ubuntu 9.2-0ubuntu1~20.04) 9.2
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from ./main...
# set target "target remote :portnumber"
(gdb) target remote :54105
Remote debugging using :54105
warning: remote target does not support file transfer, attempting to access files from local filesystem.
Reading symbols from /lib64/ld-linux-x86-64.so.2...
(No debugging symbols found in /lib64/ld-linux-x86-64.so.2)
0x00007fa7bbbcc100 in ?? () from /lib64/ld-linux-x86-64.so.2
# suspend program at main function
(gdb) break main
Breakpoint 1 at 0x2c9c: file /home/borrow/source/repos/se-test/main.cpp, line 165.
# start program execution from the beginning of the program
(gdb) run
The "remote" target does not support "run". Try "help target" or
"continue".
# step to next line of code
(gdb) step
Cannot find bounds of current function
# continue executing until next break point
(gdb) c
Continuing.
warning: Probes-based dynamic linker interface failed.
Reverting to original interface.
[Inferior 1 (Remote target) exited normally]
在window#2：如你所见
gdb run 应该 运行 一个程序，但它不起作用。 gdb c 也应该 运行 直到下一个断点但执行程序并终止。此命令给我以下警告消息：
warning: Probes-based dynamic linker interface failed.
在 window #1 中：程序 运行 结束（没有停止）。
程序代码如下所示：
// main.cpp
#include <immintrin.h>
const int N=64;
int64_t srcA[N] = {0};
int64_t srcB[N] = {0};
int64_t dst[N] = {0};
void foo()
{
__m512i result,B,C;
for ( int i=0; i<N; i+=8 ){
B = _mm512_loadu_si512(&srcA[i]);
C = _mm512_loadu_si512(&srcB[i]);
result = _mm512_add_epi64(B,C);
_mm512_storeu_si512(&dst[i], result);
}
}
int main() {
...
foo();
...
}
我尝试 运行使用 gdb 在没有 SDE 模拟器的情况下使用 AVX2 代码，它成功了。首先，我在带有 SDE 的模拟 CPU 上启动它，它失败了。我该如何解决这个问题？
PIE 可执行文件似乎已损坏
（在 Arch GNU/Linux 上使用 GCC 10.2、GDB 10.1、SDE 8.33 确认。）
使用 g++ -O2 -fno-pie -no-pie -g -march=skylake-avx512 构建，一切正常。 （我不得不 运行 gdb ./a.out 而不是裸 GDB；否则即使连接到远程也找不到正确的文件。）
$ g++ -O2 -march=skylake-avx512 -no-pie -fno-pie -g avx512.cpp
$ /opt/sde-external-8.33.0-2019-02-07-lin/sde64 -debug -- ./a.out
Application stopped until continued from debugger.
Start GDB, then issue this command at the (gdb) prompt:
target remote :59783
然后在另一个终端选项卡中
$ gdb ./a.out
...
(gdb) target remote :59783
warning: remote target does not support file transfer, attempting to access files from local filesystem.
Reading symbols from /lib64/ld-linux-x86-64.so.2...
(No debugging symbols found in /lib64/ld-linux-x86-64.so.2)
0x00007f4f7033b090 in _start () from /lib64/ld-linux-x86-64.so.2
(gdb) b main
Breakpoint 1 at 0x401050: file avx512.cpp, line 29.
(gdb) b foo
Breakpoint 2 at 0x401190: file avx512.cpp, line 14.
(gdb) c
Continuing.
Breakpoint 1, main () at avx512.cpp:23
(gdb) layout asm
(copy-paste of some of the disassembly window)
│B+ 0x401120 <_Z3foov> xor eax,eax
│ 0x401122 <_Z3foov+2> nop WORD PTR [rax+rax*1+0x0]
│ >0x401128 <_Z3foov+8> vmovdqu64 zmm1,ZMMWORD PTR [rax+0x404260]
│ 0x401132 <_Z3foov+18> add rax,0x40
│ 0x401136 <_Z3foov+22> vpaddq zmm0,zmm1,ZMMWORD PTR [rax+0x404420]
│ 0x401140 <_Z3foov+32> vmovdqu64 ZMMWORD PTR [rax+0x404020],zmm0
│ 0x40114a <_Z3foov+42> cmp rax,0x200
│ 0x401150 <_Z3foov+48> jne 0x401128 <_Z3foov+8>
│ 0x401152 <_Z3foov+50> vzeroupper
│ 0x401155 <_Z3foov+53> ret
(gdb) layout src
asm 级和源代码级调试都工作正常，在使用 stepi（又名 si）时进入 avx512fintrin.h 中的内在“功能”等。
在连接到远程时不单独指定文件名：
$ gdb
(gdb) target remote :46879
Remote debugging using :46879 warning: No executable has been specified and target does not support determining executable automatically. Try using the "file" command.
0x00007f0f85830090 in ?? ()
(gdb)
（IDK 如果我的 .gdbinit 包括 layout reg，全屏终端 TUI 模式很重要。它工作时很好，但有点错误。）
或者作为 PIE 可执行文件的超级 hacky 解决方法，我还能够在 main 的顶部放置一个延迟循环，让您有机会在 SDE 完成执行您的之前附加然后控制-C程序。
然后我可以设置断点并开始单步执行。 （大概 sleep 或 read 系统调用会起作用）。源代码级调试似乎仍然失败，但我能够使用 layout reg 调试 asm。在附加并点击 control-C 后，我使用 set $rip = ... 和复制粘贴的地址来退出 _mm_pause() 循环。