debian/patches/jemalloc.patch

   1 From patchwork Fri Jun 19 10:56:58 2015
   2 Content-Type: text/plain; charset="utf-8"
   3 MIME-Version: 1.0
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   5 Subject: configure: Add support for jemalloc
   6 From: Alexandre DERUMIER <aderumier@odiso.com>
   7 X-Patchwork-Id: 486671
   8 Message-Id: <1434711418-20429-1-git-send-email-aderumier@odiso.com>
   9 To: qemu-devel@nongnu.org
  10 Cc: Alexandre Derumier <aderumier@odiso.com>
  11 Date: Fri, 19 Jun 2015 12:56:58 +0200
  12
  13 This adds "--enable-jemalloc" and "--disable-jemalloc" to allow linking
  14 to jemalloc memory allocator.
  15
  16 We have already tcmalloc support,
  17 but it seem to not working well with a lot of iothreads/disks.
  18
  19 The main problem is that tcmalloc use a shared thread cache of 16MB
  20 by default.
  21 With more threads, this cache is shared, and some bad garbage collections
  22 can occur if the cache is too low.
  23
  24 It's possible to tcmalloc cache increase it with a env var:
  25 TCMALLOC_MAX_TOTAL_THREAD_CACHE_BYTES=256MB
  26
  27 With default 16MB, performances are  really bad with more than 2 disks.
  28 Increasing to 256MB, it's helping but still have problem with 16 disks/iothreads.
  29
  30 Jemalloc don't have performance problem with default configuration.
  31
  32 Here the benchmark results in iops of 1 qemu vm randread 4K iodepth=32,
  33 with rbd block backend (librbd is doing a lot of memory allocation),
  34 1 iothread by disk
  35
  36 glibc malloc
  37 ------------
  38
  39 1 disk      29052
  40 2 disks     55878
  41 4 disks     127899
  42 8 disks     240566
  43 15 disks    269976
  44
  45 jemalloc
  46 --------
  47
  48 1 disk      41278
  49 2 disks     75781
  50 4 disks     195351
  51 8 disks     294241
  52 15 disks    298199
  53
  54 tcmalloc 2.2.1 default 16M cache
  55 --------------------------------
  56
  57 1 disk   37911
  58 2 disks  67698
  59 4 disks  41076
  60 8 disks  43312
  61 15 disks 37569
  62
  63 tcmalloc : 256M cache
  64 ---------------------------
  65
  66 1 disk     33914
  67 2 disks    58839
  68 4 disks    148205
  69 8 disks    213298
  70 15 disks   218383
  71
  72 Signed-off-by: Alexandre Derumier <aderumier@odiso.com>
  73 Reviewed-by: Fam Zheng <famz@redhat.com>
  74 ---
  75  configure | 29 +++++++++++++++++++++++++++++
  76  1 file changed, 29 insertions(+)
  77
  78 diff --git a/configure b/configure
  79 index 222694f..2fe1e05 100755
  80 --- a/configure
  81 +++ b/configure
  82 @@ -338,6 +338,7 @@ vhdx=""
  83  vhdx=""
  84  numa=""
  85  tcmalloc="no"
  86 +jemalloc="no"
  87
  88  # parse CC options first
  89  for opt do
  90 @@ -1149,6 +1150,10 @@ for opt do
  91    ;;
  92    --enable-tcmalloc) tcmalloc="yes"
  93    ;;
  94 +  --disable-jemalloc) jemalloc="no"
  95 +  ;;
  96 +  --enable-jemalloc) jemalloc="yes"
  97 +  ;;
  98    *)
  99        echo "ERROR: unknown option $opt"
 100        echo "Try '$0 --help' for more information"
 101 @@ -3345,6 +3352,11 @@ EOF
 102    fi
 103  fi
 104
 105 +if test "$tcmalloc" = "yes" && test "$jemalloc" = "yes" ; then
 106 +    echo "ERROR: tcmalloc && jemalloc can't be used at the same time"
 107 +    exit 1
 108 +fi
 109 +
 110  ##########################################
 111  # tcmalloc probe
 112
 113 @@ -3362,6 +3374,22 @@ EOF
 114  fi
 115
 116  ##########################################
 117 +# jemalloc probe
 118 +
 119 +if test "$jemalloc" = "yes" ; then
 120 +  cat > $TMPC << EOF
 121 +#include <stdlib.h>
 122 +int main(void) { malloc(1); return 0; }
 123 +EOF
 124 +
 125 +  if compile_prog "" "-ljemalloc" ; then
 126 +    LIBS="-ljemalloc $LIBS"
 127 +  else
 128 +    feature_not_found "jemalloc" "install jemalloc devel"
 129 +  fi
 130 +fi
 131 +
 132 +##########################################
 133  # signalfd probe
 134  signalfd="no"
 135  cat > $TMPC << EOF
 136 @@ -4573,6 +4591,7 @@ echo "snappy support    $snappy"
 137  echo "bzip2 support     $bzip2"
 138  echo "NUMA host support $numa"
 139  echo "tcmalloc support  $tcmalloc"
 140 +echo "jemalloc support  $jemalloc"
 141
 142  if test "$sdl_too_old" = "yes"; then
 143  echo "-> Your SDL version is too old - please upgrade to have SDL support"