[x265] [PATCH] Performance: Don't split threads into per-NUMA pools unless specified in cli
Steve Borho
steve at borho.org
Thu Sep 3 22:05:52 CEST 2015
On 09/03, pradeep at multicorewareinc.com wrote:
> # HG changeset patch
> # User Pradeep Ramachandran <pradeep at multicorewareinc.com>
> # Date 1441271466 -19800
> # Thu Sep 03 14:41:06 2015 +0530
> # Node ID 2421fae1de247cb6758c0ad2dbb4bd5f45f23727
> # Parent 86e9bd7dd19278fceef65fc93a06dc8746ec9daf
> 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
> monolithic 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 which
> has two sockets of 18 threads each, for example)
I haven't verified it by running it, but it LGTM
> diff -r 86e9bd7dd192 -r 2421fae1de24 doc/reST/cli.rst
> --- a/doc/reST/cli.rst Tue Sep 01 17:06:05 2015 +0530
> +++ b/doc/reST/cli.rst Thu Sep 03 14:41:06 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 86e9bd7dd192 -r 2421fae1de24 source/common/threadpool.cpp
> --- a/source/common/threadpool.cpp Tue Sep 01 17:06:05 2015 +0530
> +++ b/source/common/threadpool.cpp Thu Sep 03 14:41:06 2015 +0530
> @@ -226,8 +226,13 @@
> {
> enum { MAX_NODE_NUM = 127 };
> int cpusPerNode[MAX_NODE_NUM + 1];
> + int threadsPerPool[MAX_NODE_NUM + 2];
> + uint32_t 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] |= (1U << j);
> + }
> break;
> + }
> else if (*nodeStr == '+')
> - ;
> + {
> + threadsPerPool[numNumaNodes] += cpusPerNode[i];
> + nodeMaskPerPool[numNumaNodes] = (1U << i);
> + }
> else
> {
> int count = atoi(nodeStr);
> - cpusPerNode[i] = X265_MIN(count, cpusPerNode[i]);
> + threadsPerPool[i] = X265_MIN(count, cpusPerNode[i]);
> + nodeMaskPerPool[i] = (1U << i);
> }
>
> /* consume current node string, comma, and white-space */
> @@ -288,24 +304,31 @@
> ++nodeStr;
> }
> }
> -
> - // 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)))
> + else
> {
> - 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]);
> + for (int i = 0; i < numNumaNodes; i++)
> + {
> + threadsPerPool[numNumaNodes] += cpusPerNode[i];
> + nodeMaskPerPool[numNumaNodes] |= (1U << i);
> + }
> + }
> +
> + // 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)))
> + {
> + 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, uint32_t 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_winNodemask = nodeMask & ~(0x1 << getNumaNodeCount());
> + m_numaNodeMask = &m_winNodemask;
> +#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 +447,37 @@
>
> X265_FREE(m_workers);
> X265_FREE(m_jpTable);
> +
> +#if HAVE_LIBNUMA
> + if(m_numaNodeMask)
> + 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)(*((DWORD*)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 86e9bd7dd192 -r 2421fae1de24 source/common/threadpool.h
> --- a/source/common/threadpool.h Tue Sep 01 17:06:05 2015 +0530
> +++ b/source/common/threadpool.h Thu Sep 03 14:41:06 2015 +0530
> @@ -83,7 +83,10 @@
> sleepbitmap_t m_sleepBitmap;
> int m_numProviders;
> int m_numWorkers;
> - int m_numaNode;
> + void* m_numaNodeMask;
> +#if defined(_WIN32_WINNT) && _WIN32_WINNT >= _WIN32_WINNT_WIN7
> + DWORD m_winNodemask;
> +#endif
> bool m_isActive;
>
> JobProvider** m_jpTable;
> @@ -92,7 +95,7 @@
> ThreadPool();
> ~ThreadPool();
>
> - bool create(int numThreads, int maxProviders, int node);
> + bool create(int numThreads, int maxProviders, uint32_t nodeMask);
> bool start();
> void stopWorkers();
> void setCurrentThreadAffinity();
> @@ -103,7 +106,7 @@
>
> 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
> _______________________________________________
> x265-devel mailing list
> x265-devel at videolan.org
> https://mailman.videolan.org/listinfo/x265-devel
--
Steve Borho
More information about the x265-devel
mailing list