Commit 7b01cb97 authored by Alexandre Derumier's avatar Alexandre Derumier Committed by Paolo Bonzini
Browse files

configure: Add support for jemalloc 



This adds "--enable-jemalloc" and "--disable-jemalloc" to allow linking
to jemalloc memory allocator.

We have already tcmalloc support,
but it seem to not working well with a lot of iothreads/disks.

The main problem is that tcmalloc use a shared thread cache of 16MB
by default.
With more threads, this cache is shared, and some bad garbage collections
can occur if the cache is too low.

It's possible to tcmalloc cache increase it with a env var:
TCMALLOC_MAX_TOTAL_THREAD_CACHE_BYTES=256MB

With default 16MB, performances are  really bad with more than 2 disks.
Increasing to 256MB, it's helping but still have problem with 16 disks/iothreads.

Jemalloc don't have performance problem with default configuration.

Here the benchmark results in iops of 1 qemu vm randread 4K iodepth=32,
with rbd block backend (librbd is doing a lot of memory allocation),
1 iothread by disk

glibc malloc
------------

1 disk      29052
2 disks     55878
4 disks     127899
8 disks     240566
15 disks    269976

jemalloc
--------

1 disk      41278
2 disks     75781
4 disks     195351
8 disks     294241
15 disks    298199

tcmalloc 2.2.1 default 16M cache
--------------------------------

1 disk   37911
2 disks  67698
4 disks  41076
8 disks  43312
15 disks 37569

tcmalloc : 256M cache
---------------------------

1 disk     33914
2 disks    58839
4 disks    148205
8 disks    213298
15 disks   218383

Signed-off-by: default avatarAlexandre Derumier <aderumier@odiso.com>
Message-Id: <1434711418-20429-1-git-send-email-aderumier@odiso.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3f7a899f

configure

+28 −0
Original line number Diff line number Diff line
@@ -337,6 +337,7 @@ libssh2="" 
vhdx=""

numa=""

tcmalloc="no"

jemalloc="no"



# parse CC options first

for opt do
@@ -1143,6 +1144,10 @@ for opt do 
  ;;

  --enable-tcmalloc) tcmalloc="yes"

  ;;

  --disable-jemalloc) jemalloc="no"

  ;;

  --enable-jemalloc) jemalloc="yes"

  ;;

  *)

      echo "ERROR: unknown option $opt"

      echo "Try '$0 --help' for more information"
@@ -1367,6 +1372,7 @@ disabled with --disable-FEATURE, default is enabled if available: 
  vhdx            support for the Microsoft VHDX image format

  numa            libnuma support

  tcmalloc        tcmalloc support

  jemalloc        jemalloc support



NOTE: The object files are built at the place where configure is launched

EOF
@@ -3367,6 +3373,11 @@ EOF 
  fi

fi



if test "$tcmalloc" = "yes" && test "$jemalloc" = "yes" ; then

    echo "ERROR: tcmalloc && jemalloc can't be used at the same time"

    exit 1

fi



##########################################

# tcmalloc probe
@@ -3383,6 +3394,22 @@ EOF 
  fi

fi



##########################################

# jemalloc probe



if test "$jemalloc" = "yes" ; then

  cat > $TMPC << EOF

#include <stdlib.h>

int main(void) { malloc(1); return 0; }

EOF



  if compile_prog "" "-ljemalloc" ; then

    LIBS="-ljemalloc $LIBS"

  else

    feature_not_found "jemalloc" "install jemalloc devel"

  fi

fi



##########################################

# signalfd probe

signalfd="no"
@@ -4594,6 +4621,7 @@ echo "snappy support $snappy" 
echo "bzip2 support     $bzip2"

echo "NUMA host support $numa"

echo "tcmalloc support  $tcmalloc"

echo "jemalloc support  $jemalloc"



if test "$sdl_too_old" = "yes"; then

echo "-> Your SDL version is too old - please upgrade to have SDL support"