SCP: NAT poll() optimizations

- Manage poll() file descriptors more efficiently. Both Linux() poll and Windows WSAPoll() ignore file descriptors that are negative in the pollfd array. Set the pollfd.fd file descriptor to INVALID_SOCKET when no longer needed. Reuse the pollfd array element if have_valid_socket() returns false. - sim_slirp_dispatch(): Removed, empty function no longer required. - sim_deb: Remove code that NULLs this FILE pointer when "flushing" the debug output. Presumably, closing the file and re-opening it flushes the debug output. Synchronizing when this operation occurs with other code in other threads also write to sim_deb needs to be revisited. For the time being, just fflush(sim_deb). Otherwise, _sim_debug_write_all() gets stuck in an infinite loop writing zero bytes.
bscottm · Dec 23, 2024 · 294e970 · 294e970
1 parent b530e8d
commit 294e970
Show file tree

Hide file tree

Showing 15 changed files with 316 additions and 218 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -226,6 +226,12 @@ option(SIMH_PACKAGE_SUFFIX
 option(MAC_UNIVERSAL
        "macOS universal binary flag: TRUE -> build universal binaries, FALSE -> don't."
        ${MAC_UNIVERSAL_OPTVAL})
+option(USE_SELECT
+       "NAT(libslirp): Use select() as the socket polling function"
+       FALSE)
+option(USE_POLL
+       "NAT(libslirp): Use poll() as the socket polling function"
+       FALSE)
 
 # Places where CMake should look for dependent package configuration fragments and artifacts:
 set(SIMH_PREFIX_PATH_LIST)

diff --git a/cmake/add_simulator.cmake b/cmake/add_simulator.cmake
@@ -99,8 +99,8 @@ function(build_simcore _targ)
                     ${CMAKE_SOURCE_DIR}/libslirp/src
                     ${CMAKE_BINARY_DIR}/libslirp/build-include
             )
-        endif ()
-        
+        endif ()    
+
         target_link_options(${lib} PRIVATE ${EXTRA_TARGET_LFLAGS})
 
         # Make sure that the top-level directory is part of the libary's include path:

diff --git a/cmake/cmake-builder.ps1 b/cmake/cmake-builder.ps1
@@ -72,9 +72,9 @@ param (
     ## 
     ## Supported flavors:
     ## ------------------
-    ## vs2022          Visual Studio 2022 (default)
+    ## vs2022          Visual Studio 2022
     ## vs2022-xp       Visual Studio 2022 XP compat
-    ## vs2022-x64      Visual Studio 2022 64-bit
+    ## vs2022-x64      Visual Studio 2022 64-bit (default)
     ## vs2019          Visual Studio 2019
     ## vs2019-xp       Visual Studio 2019 XP compat
     ## vs2019-x64      Visual Studio 2019 64-bit
@@ -166,6 +166,14 @@ param (
     [Parameter(Mandatory=$false)]
     [string] $sanitizer      = "",
 
+    ## Use select() as the NAT(libslirp) socket polling function
+    [Parameter(Mandatory=$false)]
+    [switch] $use_select     = $false,
+
+    ## Use WSAPoll() as the NAT(libslirp) socket polling function
+    [Parameter(Mandatory=$false)]
+    [switch] $use_poll      = $false,
+
     ## Turn on maximal compiler warnings for Debug builds (e.g. "-Wall" or "/W3")
     [Parameter(Mandatory=$false)]
     [switch] $debugWall      = $false,
@@ -207,7 +215,7 @@ class GeneratorInfo
 ## Multiple build configurations selected at compile time
 $multiConfig = $false
 ## Single configuration selected at configuration time
-$singleConfig = $true
+$singleConfig = $True
 
 $cmakeGenMap = @{
     "vs2022"      = [GeneratorInfo]::new("Visual Studio 17 2022", $multiConfig,  $false, "", @("-A", "Win32"));
@@ -391,6 +399,15 @@ else
   }
 }
 
+## Can only have one of use_select or use_poll
+if ($use_select -and $use_poll)
+{
+    Write-Host ""
+    Write-Host "!! ${scriptName}: Can only set one of -use_select, -use_poll"
+    Write-Host ""
+    exit 0
+}
+
 if (($scriptPhases -contains "generate") -or ($scriptPhases -contains "build"))
 {
     ## Clean out the build subdirectory
@@ -457,16 +474,26 @@ if (($scriptPhases -contains "generate") -or ($scriptPhases -contains "build"))
     {
         $generateArgs += @("-DSIMH_PACKAGE_SUFFIX:Bool=${cpack_suffix}")
     }
+    if ($use_select)
+    {
+        $generateArgs += @("-DUSE_SELECT:Bool=True")
+    }
+    if ($use_poll)
+    {
+        $generateArgs += @("-DUSE_POLL:Bool=True")
+    }
 
     ## Add sanitizer(s)
-    foreach ($santhing in $sanitizer.Split(',')) {
-        switch -exact ($santhing)
-        {
-            "address" {
-                $generateArgs += @("-DSANITIZE_ADDRESS:Bool=On")
-            }
-            default {
-                Write-Host "** Unknown sanitizer option: ${santhing}, ignoring"
+    if (![String]::IsNullOrEmpty($sanitizer)) {
+        foreach ($santhing in $sanitizer.Split(',')) {
+            switch -exact ($santhing)
+            {
+                "address" {
+                    $generateArgs += @("-DSANITIZE_ADDRESS:Bool=On")
+                }
+                default {
+                    Write-Host "** Unknown sanitizer option: ${santhing}, ignoring"
+                }
             }
         }
     }

diff --git a/cmake/cmake-builder.sh b/cmake/cmake-builder.sh
@@ -41,6 +41,10 @@ Configure and build simh simulators on Linux and *nix-like platforms.
                     memory  [MSan  -- memory sanitizer]
                     thread  [TSan  -- thread sanitizer]
                     undef   [UBSan -- undefined behavior sanitizer]
+--use-select      Use select() as the NAT(libslirp) socket polling
+                  function
+--use-poll        Use poll() as the NAT(libslirp) socket polling
+                  function, if available.
 
 --cpack_suffix    Specify CPack's packaging suffix, e.g., "ubuntu-22.04"
                   to produce the "simh-4.1.0-ubuntu-22.04.deb" Debian
@@ -169,7 +173,7 @@ fi
 
 longopts=clean,help,flavor:,config:,nonetwork,novideo,notest,parallel,generate,testonly
 longopts=${longopts},noinstall,installonly,verbose,target:,lto,debugWall,cppcheck,cpack_suffix:
-longopts=${longopts},cache,no-aio,no-aio-intrinsics,sanitizer:
+longopts=${longopts},cache,no-aio,no-aio-intrinsics,sanitizer:,use-select,use-poll
 
 ARGS=$(${getopt_prog} --longoptions $longopts --options xhf:c:pg -- "$@")
 if [ $? -ne 0 ] ; then
@@ -313,6 +317,14 @@ while true; do
             esac
             shift 2
             ;;
+        --use-select)
+            generateArgs="${generateArgs} -DUSE_SELECT:Bool=True"
+            shift
+            ;;
+        --use-poll)
+            generateArgs="${generateArgs} -DUSE_POLL:Bool=True"
+            shift
+            ;;
         --)
             ## End of options. we'll ignore.
             shift

diff --git a/cmake/os-features.cmake b/cmake/os-features.cmake
@@ -182,20 +182,6 @@ if (WITH_NETWORK)
     endif (WITH_TAP)
 endif (WITH_NETWORK)
 
-## Windows: winmm (for ms timer functions), socket functions (even when networking is
-## disabled. Also squelch the deprecation warnings (these warnings can be enabled
-## via the -DWINAPI_DEPRECATION:Bool=On flag at configure time.)
-if (WIN32)
-    target_link_libraries(os_features INTERFACE ws2_32 wsock32 winmm)
-    target_compile_definitions(os_features INTERFACE HAVE_WINMM)
-    if (NOT WINAPI_DEPRECATION)
-        target_compile_definitions(os_features INTERFACE
-            _CRT_NONSTDC_NO_WARNINGS
-            _CRT_SECURE_NO_WARNINGS
-        )
-    endif ()
-endif ()
-
 ## Cygwin also wants winmm. Note: Untested but should work.
 if (CYGWIN)
   check_library_exists(winmm timeGetTime "" HAS_WINMM)
@@ -215,31 +201,53 @@ endif ()
 set(sim_use_select 0)
 set(sim_use_poll   0)
 
-if (NOT WIN32)
-    check_include_file(poll.h have_poll_h)
-    if (have_poll_h)
-        set(sim_use_poll   1)
-    else ()
-        set(sim_use_select 1)
-    endif ()
-else ()
-    cmake_push_check_state()
-    list(APPEND CMAKE_REQUIRED_LIBRARIES "ws2_32")
+set(check_poll     0)
 
-    check_symbol_exists(WSAPoll "winsock2.h;windows.h" have_wsa_poll)
-    if (have_wsa_poll)
-        set(sim_use_poll   1)
+if (USE_SELECT)
+    set(sim_use_select 1)
+else ()
+    if (NOT WIN32)
+        check_symbol_exists(poll "poll.h" have_poll_h)
+        if (have_poll_h)
+            set(sim_use_poll   1)
+        elseif (USE_POLL)
+            message(FATAL_ERROR "USE_POLL set, poll.h not detected. Select a different socket polling mechansim.")
+        else ()
+            set(sim_use_select 1)
+        endif()
     else ()
-        set(sim_use_select 1)
-    endif ()
+        cmake_push_check_state()
+        list(APPEND CMAKE_REQUIRED_LIBRARIES "ws2_32" "wsock32")
 
-    cmake_pop_check_state()
-endif()
+        check_symbol_exists(WSAPoll "winsock2.h;windows.h" have_wsa_poll)
+        if (have_wsa_poll)
+            set(sim_use_poll  1)
+        else ()
+            set(sim_use_select 1)
+        endif ()
+
+        cmake_pop_check_state()
+    endif()
+endif ()
 
-target_compile_definitions(os_features INTERFACE 
+target_compile_definitions(os_features INTERFACE
     SIM_USE_POLL=${sim_use_poll}
     SIM_USE_SELECT=${sim_use_select}
 )
 
+## Windows: winmm (for ms timer functions), socket functions (even when networking is
+## disabled. Also squelch the deprecation warnings (these warnings can be enabled
+## via the -DWINAPI_DEPRECATION:Bool=On flag at configure time.)
+if (WIN32)
+    target_link_libraries(os_features INTERFACE ws2_32 wsock32 winmm)
+    target_compile_definitions(os_features INTERFACE HAVE_WINMM)
+    if (NOT WINAPI_DEPRECATION)
+        target_compile_definitions(os_features INTERFACE
+            _CRT_NONSTDC_NO_WARNINGS
+            _CRT_SECURE_NO_WARNINGS
+        )
+    endif ()
+endif ()
+
 ## Sanitizer support
 find_package(Sanitizers)
diff --git a/cmake/platform-quirks.cmake b/cmake/platform-quirks.cmake
@@ -132,6 +132,37 @@ if (WIN32)
         message(STATUS "Target Windows version set to ${TARGET_WINVER}")
         add_compile_definitions(WINVER=${TARGET_WINVER} _WIN32_WINNT=${TARGET_WINVER})
         list(APPEND CMAKE_REQUIRED_DEFINITIONS "-DWINVER=${TARGET_WINVER}" "-D_WIN32_WINNT=${TARGET_WINVER}")
+        set(WINVER ${TARGET_WINVER})
+    else ()
+        file(WRITE
+            ${CMAKE_BINARY_DIR}/CMakeTmp/testWinVer.c
+            "#define WINDOWS_LEAN_AND_MEAN\n"
+            "#include <windows.h>\n"
+            "#include <stdio.h>\n"
+            "int main(void) {\n"
+            "#if defined(WINVER) && WINVER >= 0x0601\n"
+            "   return 0;\n"
+            "#else\n"
+            "   return 1;\n"
+            "#endif\n"
+            "}\n"
+        )
+
+        try_run(RUN_WINVER COMPILE_WINVER
+            SOURCES ${CMAKE_BINARY_DIR}/CMakeTmp/testWinVer.c
+            RUN_OUTPUT_VARIABLE THE_WINVER
+        )
+
+        if (RUN_WINVER EQUAL 0)
+            message(STATUS "Windows Vista or later.")
+            set(WINDOWS_VISTA_PLUS TRUE)
+        else ()
+            message(STATUS "Windows version not detected: run status ${RUN_WINVER}, compile status ${COMPILE_WINVER}")
+            set(WINDOWS_VISTA_PLUS FALSE)
+            endif ()
+
+        unset(RUN_WINVER)
+        unset(COMPILE_WINVER)
     endif ()
 elseif (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
     # The MSVC solution builds as 32-bit, but none of the *nix platforms do.
@@ -223,8 +254,6 @@ if (CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_ID MATCHES ".*Clang")
         string(REGEX REPLACE "${opt_flag}[ \t\r\n]*" "" CMAKE_C_FLAGS_MINSIZEREL "${CMAKE_C_FLAGS_MINSIZEREL}")
         string(APPEND CMAKE_C_FLAGS_MINSIZEREL " ${opt_flag}")
     endforeach ()
-else ()
-    message(STATUS "Not changing CMAKE_C_FLAGS_RELEASE on ${CMAKE_C_COMPILER_ID}")
 endif ()
 
 

diff --git a/libslirp b/libslirp