Support jemalloc as the default allocator on Linux (#7250)

Add jemalloc as an alternative malloc implementation for the Verilator binary. When both tcmalloc and jemalloc are available, jemalloc is preferred due to its better performance on RTLMeter. The new --enable-jemalloc flag (default=check) mirrors the existing --enable-tcmalloc behavior: auto-detected at configure time, supports both static and dynamic linking, and is disabled when --enable-dev-asan is active.
2026-03-14 05:08:15 +08:00 · 2026-03-14 05:08:15 +08:00 · bb5a9dc247
parent 7cd49a8028
commit bb5a9dc247
8 changed files with 78 additions and 12 deletions
--- a/.github/workflows/reusable-rtlmeter-build.yml
+++ b/.github/workflows/reusable-rtlmeter-build.yml
@ -36,8 +36,8 @@ jobs:
          echo "path-exclude /usr/share/info/*" | sudo tee -a /etc/dpkg/dpkg.cfg.d/01_nodoc
          sudo apt update || \
          sudo apt update
-          sudo apt install ccache mold help2man libfl-dev libgoogle-perftools-dev libsystemc-dev || \
-          sudo apt install ccache mold help2man libfl-dev libgoogle-perftools-dev libsystemc-dev
+          sudo apt install ccache mold help2man libfl-dev libjemalloc-dev libsystemc-dev || \
+          sudo apt install ccache mold help2man libfl-dev libjemalloc-dev libsystemc-dev

      - name: Use saved ccache
        uses: actions/cache@v5
--- a/.github/workflows/reusable-rtlmeter-run.yml
+++ b/.github/workflows/reusable-rtlmeter-run.yml
@ -60,8 +60,8 @@ jobs:
          echo "path-exclude /usr/share/info/*" | sudo tee -a /etc/dpkg/dpkg.cfg.d/01_nodoc
          sudo apt update || \
          sudo apt update
-          sudo apt install ccache mold libfl-dev libgoogle-perftools-dev libsystemc-dev || \
-          sudo apt install ccache mold libfl-dev libgoogle-perftools-dev libsystemc-dev
+          sudo apt install ccache mold libfl-dev libjemalloc-dev libsystemc-dev || \
+          sudo apt install ccache mold libfl-dev libjemalloc-dev libsystemc-dev

      - name: Download Verilator installation archive
        uses: actions/download-artifact@v8
--- a/ci/ci-install.bash
+++ b/ci/ci-install.bash
@ -60,8 +60,8 @@ if [ "$CI_BUILD_STAGE_NAME" = "build" ]; then
    sudo apt-get install ccache help2man libfl-dev
    if [[ ! "$CI_RUNS_ON" =~ "ubuntu-22.04" ]]; then
      # Some conflict of libunwind verison on 22.04, can live without it for now
-      sudo apt-get install libgoogle-perftools-dev ||
-      sudo apt-get install libgoogle-perftools-dev
+      sudo apt-get install libjemalloc-dev ||
+      sudo apt-get install libjemalloc-dev
    fi
    if [[ "$CI_RUNS_ON" =~ "ubuntu-20.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-22.04" ]] || [[ "$CI_RUNS_ON" =~ "ubuntu-24.04" ]]; then
      sudo apt-get install libsystemc libsystemc-dev ||
--- a/ci/docker/buildenv/Dockerfile
+++ b/ci/docker/buildenv/Dockerfile
@ -37,7 +37,7 @@ RUN apt-get update \
                        libfl2 \
                        libfl-dev \
                        libclang-rt-18-dev \
-                        libgoogle-perftools-dev \
+                        libjemalloc-dev \
                        libsystemc \
                        libsystemc-dev \
                        numactl \
--- a/ci/docker/run/Dockerfile
+++ b/ci/docker/run/Dockerfile
@ -22,7 +22,7 @@ RUN apt-get update \
                        help2man \
                        libfl2 \
                        libfl-dev \
-                        libgoogle-perftools-dev \
+                        libjemalloc-dev \
                        numactl \
                        perl \
                        perl-doc \
--- a/configure.ac
+++ b/configure.ac
@ -64,8 +64,8 @@ AC_ARG_ENABLE([dev-asan],
              [AS_HELP_STRING([--enable-dev-asan],
                              [Enable compiling Verilator with ASAN
                               AddressSanitizer for memory error detection.
-                               This disables tcmalloc.  Does not affect
-                               Verilated models using ASAN.])],
+                               This disables tcmalloc and jemalloc.  Does not
+                               affect Verilated models using ASAN.])],
              [case "${enableval}" in
                yes) CFG_WITH_DEV_ASAN=yes ;;
                no)  CFG_WITH_DEV_ASAN=no ;;
@ -93,6 +93,27 @@ else
  AC_MSG_RESULT($CFG_WITH_TCMALLOC)
 fi

+# Flag to enable linking Verilator with jemalloc if available
+AC_MSG_CHECKING(whether to use jemalloc)
+AC_ARG_ENABLE([jemalloc],
+              [AS_HELP_STRING([--enable-jemalloc],
+                              [Use libjemalloc for faster dynamic memory
+                               management in Verilator binary. Preferred over
+                               tcmalloc when both are available
+                               @<:@default=check@:>@])],
+              [case "${enableval}" in
+                yes) CFG_WITH_JEMALLOC=yes ;;
+                no)  CFG_WITH_JEMALLOC=no ;;
+                *)   AC_MSG_ERROR([bad value '${enableval}' for --enable-jemalloc]) ;;
+               esac],
+              [CFG_WITH_JEMALLOC=check;])
+if test "$CFG_WITH_DEV_ASAN" = "yes"; then
+  CFG_WITH_JEMALLOC=no
+  AC_MSG_RESULT("disabled by --enable-dev-asan")
+else
+  AC_MSG_RESULT($CFG_WITH_JEMALLOC)
+fi
+
 # Flag to enable code coverage build with gcov
 AC_MSG_CHECKING(whether to build for gcov code coverage collection)
 AC_ARG_ENABLE([dev-gcov],
@ -567,8 +588,10 @@ if test "$CFG_ENABLE_PARTIAL_STATIC" = "yes"; then
  _MY_LDLIBS_CHECK_OPT(CFG_LDFLAGS_SRC, -static-libstdc++)
  _MY_LDLIBS_CHECK_OPT(CFG_LDFLAGS_SRC, -Xlinker -gc-sections)
  LTCMALLOC="-Wl,--whole-archive -l:libtcmalloc_minimal.a -Wl,--no-whole-archive"
+  LJEMALLOC="-Wl,--whole-archive -l:libjemalloc.a -Wl,--no-whole-archive"
 else
  LTCMALLOC=-ltcmalloc_minimal
+  LJEMALLOC=-ljemalloc
 fi
 AC_SUBST(CFG_LDFLAGS_SRC)
 AC_SUBST(CFG_LDFLAGS_VERILATED)
@ -584,11 +607,38 @@ _MY_LDLIBS_CHECK_OPT(CFG_LIBS, -latomic)
 _MY_LDLIBS_CHECK_OPT(CFG_LIBS, -lbcrypt)
 _MY_LDLIBS_CHECK_OPT(CFG_LIBS, -lpsapi)

+# Check if jemalloc is available based on --enable-jemalloc
+# jemalloc is preferred over tcmalloc when both are available
+CFG_HAVE_JEMALLOC=no
+_MY_LDLIBS_CHECK_IFELSE(
+  $LJEMALLOC,
+  [if test "$CFG_WITH_JEMALLOC" != "no"; then
+    CFG_LIBS="$LJEMALLOC $CFG_LIBS";
+    CFG_HAVE_JEMALLOC=yes;
+    # If using jemalloc, add some extra options to make the compiler not assume
+    # it is using its own versions of the standard library functions
+    _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_SRC,-fno-builtin-malloc)
+    _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_SRC,-fno-builtin-calloc)
+    _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_SRC,-fno-builtin-realloc)
+    _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_SRC,-fno-builtin-free)
+    AC_DEFINE([HAVE_JEMALLOC],[1],[Defined if have jemalloc])
+   fi],
+  [if test "$CFG_WITH_JEMALLOC" = "yes"; then
+    AC_MSG_ERROR([--enable-jemalloc was given but test for ${LJEMALLOC} failed])
+   fi])
+AC_SUBST(HAVE_JEMALLOC)
+
 # Check if tcmalloc is available based on --enable-tcmalloc
+# Only use tcmalloc if jemalloc was not found/enabled
+if test "$CFG_HAVE_JEMALLOC" = "yes"; then
+  AC_MSG_NOTICE([jemalloc found, skipping tcmalloc check])
+else
+CFG_HAVE_TCMALLOC=no
 _MY_LDLIBS_CHECK_IFELSE(
  $LTCMALLOC,
  [if test "$CFG_WITH_TCMALLOC" != "no"; then
    CFG_LIBS="$LTCMALLOC $CFG_LIBS";
+    CFG_HAVE_TCMALLOC=yes;
    # If using tcmalloc, add some extra options to make the compiler not assume
    # it is using its own versions of the standard library functions
    _MY_CXX_CHECK_OPT(CFG_CXXFLAGS_SRC,-fno-builtin-malloc)
@ -600,6 +650,7 @@ _MY_LDLIBS_CHECK_IFELSE(
  [if test "$CFG_WITH_TCMALLOC" = "yes"; then
    AC_MSG_ERROR([--enable-tcmalloc was given but test for ${LTCMALLOC} failed])
   fi])
+fi
 AC_SUBST(HAVE_TCMALLOC)
 AC_SUBST(CFG_LIBS)

--- a/docs/guide/install.rst
+++ b/docs/guide/install.rst
@ -61,7 +61,7 @@ In brief, to install from git:

   # Prerequisites:
   #sudo apt-get install git help2man perl python3 make autoconf g++ flex bison ccache
-   #sudo apt-get install libgoogle-perftools-dev numactl perl-doc
+   #sudo apt-get install libgoogle-perftools-dev libjemalloc-dev numactl perl-doc
   #sudo apt-get install libfl2  # Ubuntu only (ignore if gives error)
   #sudo apt-get install libfl-dev  # Ubuntu only (ignore if gives error)
   #sudo apt-get install zlibc zlib1g zlib1g-dev  # Ubuntu only (ignore if gives error)
@ -144,7 +144,7 @@ installed for good performance:

   sudo apt-get install ccache  # If present at build, needed for run
   sudo apt-get install mold  # If present at build, needed for run
-   sudo apt-get install libgoogle-perftools-dev numactl
+   sudo apt-get install libjemalloc-dev numactl

 To build Verilator you will need to install these packages; these do not
 need to be present to run Verilator:
--- a/src/V3Os.cpp
+++ b/src/V3Os.cpp
@ -57,6 +57,9 @@ VL_DEFINE_DEBUG_FUNCTIONS;
 #ifdef HAVE_TCMALLOC
 #include <gperftools/malloc_extension.h>
 #endif
+#ifdef HAVE_JEMALLOC
+#include <jemalloc/jemalloc.h>
+#endif

 // clang-format off
 #if defined(_WIN32) || defined(__MINGW32__)
@ -413,6 +416,18 @@ void V3Os::releaseMemory() {
 #ifdef HAVE_TCMALLOC
    MallocExtension::instance()->ReleaseFreeMemory();
 #endif
+#ifdef HAVE_JEMALLOC
+    // Purge all unused dirty pages across all arenas
+    unsigned narenas = 0;
+    size_t sz = sizeof(narenas);
+    if (mallctl("arenas.narenas", &narenas, &sz, nullptr, 0)) {
+        return;  // Failed to get number of arenas, give up
+    }
+    char buf[64];
+    // Index equal to narenas represents all arenas
+    VL_SNPRINTF(buf, sizeof(buf), "arena.%u.purge", narenas);
+    mallctl(buf, nullptr, nullptr, nullptr, 0);
+#endif
 }

 //######################################################################