[x265] [PATCH] Performance: Don't split threads into per-NUMA pools unless specified in cli

Pradeep Ramachandran pradeep at multicorewareinc.com
Tue Sep 1 10:54:04 CEST 2015


Looks like this doesn't apply to the head... grrr...
Apologies for the mistake - will resend a fixed patch.

Pradeep Ramachandran, PhD
Solution Architect,
Multicoreware Inc.
Ph:   +91 99627 82018

On Tue, Sep 1, 2015 at 1:51 PM, <pradeep at multicorewareinc.com> wrote:

> # HG changeset patch
> # User Pradeep Ramachandran <pradeep at multicorewareinc.com>
> # Date 1441095610 -19800
> #      Tue Sep 01 13:50:10 2015 +0530
> # Node ID eda792e5d9c746e099879e8e58211f7807b88075
> # Parent  9f669a8d959e557c7ea2cc7be59c807dc5b8dee2
> Performance: Don't split threads into per-NUMA pools unless specified in
> cli
>
> Fixes the threadpools to store a numa node mask instead of a numa node id
> to
> use liNUMA functionality, and changes default thread pool behavior to use
> one
> monolythic pool
>
> We see gains of 10%+ on Intel Xeon E5-2666v3, E5-2640 v2 machines for 4K
> videos
> encoding at an ABR of 15Mbps in slower and versylow settings. Ultrafast
> shows a
> perf dip of ~8% on the same machines. So when running in ultrafast mode,
> explicilty
> specify # threads with the --pools command (--pools 18,18 on the E5-2666v3
> for
> example)
>
> diff -r 9f669a8d959e -r eda792e5d9c7 doc/reST/cli.rst
> --- a/doc/reST/cli.rst  Tue Sep 01 11:38:47 2015 +0530
> +++ b/doc/reST/cli.rst  Tue Sep 01 13:50:10 2015 +0530
> @@ -202,15 +202,29 @@
>         "-"       - same as "none"
>         "10"      - allocate one pool, using up to 10 cores on node 0
>         "-,+"     - allocate one pool, using all cores on node 1
> -       "+,-,+"   - allocate two pools, using all cores on nodes 0 and 2
> -       "+,-,+,-" - allocate two pools, using all cores on nodes 0 and 2
> -       "-,*"     - allocate three pools, using all cores on nodes 1, 2
> and 3
> +       "+,-,+"   - allocate one pool, using only cores on nodes 0 and 2
> +       "+,-,+,-" - allocate one pool, using only cores on nodes 0 and 2
> +       "-,*"     - allocate one pool, using all cores on nodes 1, 2 and 3
>         "8,8,8,8" - allocate four pools with up to 8 threads in each pool
> +       "8,+,+,+" - allocate two pools, the first with 8 threads on node
> 0, and the second with all cores on node 1,2,3
>
> -       The total number of threads will be determined by the number of
> threads
> -       assigned to all nodes. The worker threads will each be given
> affinity for
> -       their node, they will not be allowed to migrate between nodes, but
> they
> -       will be allowed to move between CPU cores within their node.
> +       A thread pool dedicated to a given NUMA node is enabled only when
> the
> +       number of threads to be created on that NUMA node is explicitly
> mentioned
> +       in that corresponding position with the --pools option. Else, all
> threads
> +       are spawned from a single pool. The total number of threads will be
> +       determined by the number of threads assigned to the enabled NUMA
> nodes for
> +       that pool. The worker threads are be given affinity to all the
> enabled
> +       NUMA nodes for that pool and may migrate between them, unless
> explicitly
> +       specified as described above.
> +
> +       In the case that any threadpool has more than 64 threads, the
> threadpool
> +       may be broken down into multiple pools of 64 threads each; on
> 32-bit
> +       machines, this number is 32. All pools are given affinity to the
> NUMA
> +       nodes on which the original pool had affinity. For performance
> reasons,
> +       the last thread pool is spawned only if it has more than 32
> threads for
> +       64-bit machines, or 16 for 32-bit machines. If the total number of
> threads
> +       in the system doesn't obey this constraint, we may spawn fewer
> threads
> +       than cores which has been emperically shown to be better for
> performance.
>
>         If the four pool features: :option:`--wpp`, :option:`--pmode`,
>         :option:`--pme` and :option:`--lookahead-slices` are all disabled,
> @@ -219,10 +233,6 @@
>         If "none" is specified, then all four of the thread pool features
> are
>         implicitly disabled.
>
> -       Multiple thread pools will be allocated for any NUMA node with
> more than
> -       64 logical CPU cores. But any given thread pool will always use at
> most
> -       one NUMA node.
> -
>         Frame encoders are distributed between the available thread pools,
>         and the encoder will never generate more thread pools than
>         :option:`--frame-threads`.  The pools are used for WPP and for
> @@ -238,8 +248,12 @@
>         system, a POSIX build of libx265 without libnuma will be less work
>         efficient. See :ref:`thread pools <pools>` for more detail.
>
> -       Default "", one thread is allocated per detected hardware thread
> -       (logical CPU cores) and one thread pool per NUMA node.
> +       Default "", one pool is created across all available NUMA nodes,
> with
> +       one thread allocated per detected hardware thread
> +       (logical CPU cores). In the case that the total number of threads
> is more
> +       than the maximum size that ATOMIC operations can handle (32 for
> 32-bit
> +       compiles, and 64 for 64-bit compiles), multiple thread pools may be
> +       spawned subject to the performance constraint described above.
>
>         Note that the string value will need to be escaped or quoted to
>         protect against shell expansion on many platforms
> diff -r 9f669a8d959e -r eda792e5d9c7 source/common/threadpool.cpp
> --- a/source/common/threadpool.cpp      Tue Sep 01 11:38:47 2015 +0530
> +++ b/source/common/threadpool.cpp      Tue Sep 01 13:50:10 2015 +0530
> @@ -226,8 +226,13 @@
>  {
>      enum { MAX_NODE_NUM = 127 };
>      int cpusPerNode[MAX_NODE_NUM + 1];
> +    int threadsPerPool[MAX_NODE_NUM + 2];
> +    unsigned long nodeMaskPerPool[MAX_NODE_NUM +2];
>
>      memset(cpusPerNode, 0, sizeof(cpusPerNode));
> +    memset(threadsPerPool, 0, sizeof(threadsPerPool));
> +    memset(nodeMaskPerPool, 0, sizeof(nodeMaskPerPool));
> +
>      int numNumaNodes = X265_MIN(getNumaNodeCount(), MAX_NODE_NUM);
>      int cpuCount = getCpuCount();
>      bool bNumaSupport = false;
> @@ -258,7 +263,7 @@
>          for (int i = 0; i < numNumaNodes; i++)
>              x265_log(p, X265_LOG_DEBUG, "detected NUMA node %d with %d
> logical cores\n", i, cpusPerNode[i]);
>
> -    /* limit nodes based on param->numaPools */
> +    /* limit threads based on param->numaPools */
>      if (p->numaPools && *p->numaPools)
>      {
>          const char *nodeStr = p->numaPools;
> @@ -266,19 +271,30 @@
>          {
>              if (!*nodeStr)
>              {
> -                cpusPerNode[i] = 0;
> +                threadsPerPool[i] = 0;
>                  continue;
>              }
>              else if (*nodeStr == '-')
> -                cpusPerNode[i] = 0;
> +                threadsPerPool[i] = 0;
>              else if (*nodeStr == '*')
> +            {
> +                for(int j = i; j < numNumaNodes; j++)
> +                {
> +                    threadsPerPool[numNumaNodes] += cpusPerNode[j];
> +                    nodeMaskPerPool[numNumaNodes] |= ((unsigned long)1 <<
> j);
> +                }
>                  break;
> +            }
>              else if (*nodeStr == '+')
> -                ;
> +            {
> +                threadsPerPool[numNumaNodes] += cpusPerNode[i];
> +                nodeMaskPerPool[numNumaNodes] = ((unsigned long)1 << i);
> +            }
>              else
>              {
>                  int count = atoi(nodeStr);
> -                cpusPerNode[i] = X265_MIN(count, cpusPerNode[i]);
> +                threadsPerPool[i] = X265_MIN(count, cpusPerNode[i]);
> +                nodeMaskPerPool[i] = ((unsigned long)1 << i);
>              }
>
>              /* consume current node string, comma, and white-space */
> @@ -288,24 +304,31 @@
>                 ++nodeStr;
>          }
>      }
> +    else
> +    {
> +        for(int i = 0; i < numNumaNodes; i++)
> +        {
> +            threadsPerPool[numNumaNodes]  += cpusPerNode[i];
> +            nodeMaskPerPool[numNumaNodes] |= ((unsigned long)1 << i);
> +        }
> +    }
>
> -    // In the case that numa is disabled and we have more CPUs than 64,
> -    // spawn the last pool only if the # threads in that pool is > 1/2
> max (heuristic)
> -    if ((numNumaNodes == 1) &&
> -        (cpusPerNode[0] > MAX_POOL_THREADS) &&
> -        (cpusPerNode[0] % MAX_POOL_THREADS < (MAX_POOL_THREADS / 2)))
> +    // If the last pool size is > MAX_POOL_THREADS, clip it to spawn
> thread pools only of size >= 1/2 max (heuristic)
> +    if ((threadsPerPool[numNumaNodes] > MAX_POOL_THREADS) &&
> +       ((threadsPerPool[numNumaNodes] % MAX_POOL_THREADS) <
> (MAX_POOL_THREADS / 2)))
>      {
> -        cpusPerNode[0] -= (cpusPerNode[0] % MAX_POOL_THREADS);
> -        x265_log(p, X265_LOG_DEBUG, "Creating only %d worker threads to
> prevent asymmetry in pools; may not use all HW contexts\n", cpusPerNode[0]);
> +        threadsPerPool[numNumaNodes] -= (threadsPerPool[numNumaNodes] %
> MAX_POOL_THREADS);
> +        x265_log(p, X265_LOG_DEBUG,
> +                 "Creating only %d worker threads beyond specified
> numbers with --pools (if specified) to prevent asymmetry in pools; may not
> use all HW contexts\n", threadsPerPool[numNumaNodes]);
>      }
>
>      numPools = 0;
> -    for (int i = 0; i < numNumaNodes; i++)
> +    for (int i = 0; i < numNumaNodes + 1; i++)
>      {
>          if (bNumaSupport)
>              x265_log(p, X265_LOG_DEBUG, "NUMA node %d may use %d logical
> cores\n", i, cpusPerNode[i]);
> -        if (cpusPerNode[i])
> -            numPools += (cpusPerNode[i] + MAX_POOL_THREADS - 1) /
> MAX_POOL_THREADS;
> +        if (threadsPerPool[i])
> +            numPools += (threadsPerPool[i] + MAX_POOL_THREADS - 1) /
> MAX_POOL_THREADS;
>      }
>
>      if (!numPools)
> @@ -324,20 +347,20 @@
>          int node = 0;
>          for (int i = 0; i < numPools; i++)
>          {
> -            while (!cpusPerNode[node])
> +            while (!threadsPerPool[node])
>                  node++;
> -            int cores = X265_MIN(MAX_POOL_THREADS, cpusPerNode[node]);
> -            if (!pools[i].create(cores, maxProviders, node))
> +            int numThreads = X265_MIN(MAX_POOL_THREADS,
> threadsPerPool[node]);
> +            if (!pools[i].create(numThreads, maxProviders,
> nodeMaskPerPool[node]))
>              {
>                  X265_FREE(pools);
>                  numPools = 0;
>                  return NULL;
>              }
>              if (numNumaNodes > 1)
> -                x265_log(p, X265_LOG_INFO, "Thread pool %d using %d
> threads on NUMA node %d\n", i, cores, node);
> +                x265_log(p, X265_LOG_INFO, "Thread pool %d using %d
> threads with NUMA node mask %lx\n", i, numThreads, nodeMaskPerPool[node]);
>              else
> -                x265_log(p, X265_LOG_INFO, "Thread pool created using %d
> threads\n", cores);
> -            cpusPerNode[node] -= cores;
> +                x265_log(p, X265_LOG_INFO, "Thread pool created using %d
> threads\n", numThreads);
> +            threadsPerPool[node] -= numThreads;
>          }
>      }
>      else
> @@ -350,11 +373,27 @@
>      memset(this, 0, sizeof(*this));
>  }
>
> -bool ThreadPool::create(int numThreads, int maxProviders, int node)
> +bool ThreadPool::create(int numThreads, int maxProviders, unsigned long
> nodeMask)
>  {
>      X265_CHECK(numThreads <= MAX_POOL_THREADS, "a single thread pool
> cannot have more than MAX_POOL_THREADS threads\n");
>
> -    m_numaNode = node;
> +#if defined(_WIN32_WINNT) && _WIN32_WINNT >= _WIN32_WINNT_WIN7
> +    m_numaNodeMask = new DWORD_PTR;
> +    (*m_numaNodeMask) = nodeMask & ~(0x1 << X265_MIN(getNumaNodeCount(),
> MAX_NODE_NUM));
> +#elif HAVE_LIBNUMA
> +    if (numa_available() >= 0)
> +    {
> +        struct bitmask* nodemask = numa_allocate_nodemask();
> +        if (nodemask)
> +        {
> +            *(nodemask->maskp) = nodeMask;
> +            m_numaNodeMask = nodemask;
> +        }
> +        else
> +            x265_log(NULL, X265_LOG_ERROR, "unable to get NUMA node mask
> for %lx\n", nodeMask);
> +    }
> +#endif
> +
>      m_numWorkers = numThreads;
>
>      m_workers = X265_MALLOC(WorkerThread, numThreads);
> @@ -408,36 +447,39 @@
>
>      X265_FREE(m_workers);
>      X265_FREE(m_jpTable);
> +
> +    if(m_numaNodeMask)
> +#if defined(_WIN32_WINNT) && _WIN32_WINNT >= _WIN32_WINNT_WIN7
> +        free(m_numaNodeMask);
> +#elif HAVE_LIBNUMA
> +        numa_free_nodemask((struct bitmask*)m_numaNodeMask);
> +#endif
>  }
>
>  void ThreadPool::setCurrentThreadAffinity()
>  {
> -    setThreadNodeAffinity(m_numaNode);
> +    setThreadNodeAffinity(m_numaNodeMask);
>  }
>
>  /* static */
> -void ThreadPool::setThreadNodeAffinity(int numaNode)
> +void ThreadPool::setThreadNodeAffinity(void *numaNodeMask)
>  {
>  #if defined(_WIN32_WINNT) && _WIN32_WINNT >= _WIN32_WINNT_WIN7
> -    GROUP_AFFINITY groupAffinity;
> -    if (GetNumaNodeProcessorMaskEx((USHORT)numaNode, &groupAffinity))
> -    {
> -        if (SetThreadAffinityMask(GetCurrentThread(),
> (DWORD_PTR)groupAffinity.Mask))
> -            return;
> -    }
> -    x265_log(NULL, X265_LOG_ERROR, "unable to set thread affinity to NUMA
> node %d\n", numaNode);
> +    if (SetThreadAffinityMask(GetCurrentThread(),
> (DWORD_PTR)numaNodeMask))
> +        return;
> +    else
> +        x265_log(NULL, X265_LOG_ERROR, "unable to set thread affinity for
> NUMA node mask\n");
>  #elif HAVE_LIBNUMA
>      if (numa_available() >= 0)
>      {
> -        numa_run_on_node(numaNode);
> -        numa_set_preferred(numaNode);
> +        numa_run_on_node_mask((struct bitmask*)numaNodeMask);
> +        numa_set_interleave_mask((struct bitmask*)numaNodeMask);
>          numa_set_localalloc();
>          return;
>      }
> -    x265_log(NULL, X265_LOG_ERROR, "unable to set thread affinity to NUMA
> node %d\n", numaNode);
> -#else
> -    (void)numaNode;
> +    x265_log(NULL, X265_LOG_ERROR, "unable to set thread affinity for
> NUMA node mask\n");
>  #endif
> +    return;
>  }
>
>  /* static */
> diff -r 9f669a8d959e -r eda792e5d9c7 source/common/threadpool.h
> --- a/source/common/threadpool.h        Tue Sep 01 11:38:47 2015 +0530
> +++ b/source/common/threadpool.h        Tue Sep 01 13:50:10 2015 +0530
> @@ -83,7 +83,7 @@
>      sleepbitmap_t m_sleepBitmap;
>      int           m_numProviders;
>      int           m_numWorkers;
> -    int           m_numaNode;
> +    void*         m_numaNodeMask;
>      bool          m_isActive;
>
>      JobProvider** m_jpTable;
> @@ -92,7 +92,7 @@
>      ThreadPool();
>      ~ThreadPool();
>
> -    bool create(int numThreads, int maxProviders, int node);
> +    bool create(int numThreads, int maxProviders, unsigned long nodeMask);
>      bool start();
>      void stopWorkers();
>      void setCurrentThreadAffinity();
> @@ -103,7 +103,7 @@
>
>      static int  getCpuCount();
>      static int  getNumaNodeCount();
> -    static void setThreadNodeAffinity(int node);
> +    static void setThreadNodeAffinity(void *numaNodeMask);
>  };
>
>  /* Any worker thread may enlist the help of idle worker threads from the
> same
>
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