Yohahaha commented on code in PR #5439:
URL: https://github.com/apache/incubator-gluten/pull/5439#discussion_r1606179989
##########
gluten-core/src/main/scala/org/apache/gluten/GlutenPlugin.scala:
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@@ -164,20 +165,71 @@ private[gluten] class GlutenDriverPlugin extends
DriverPlugin with Logging {
// task slots
val taskSlots = SparkResourceUtil.getTaskSlots(conf)
- // Optimistic off-heap sizes, assuming all storage memory can be borrowed
into execution memory
- // pool, regardless of Spark option spark.memory.storageFraction.
- val offHeapSize = conf.getSizeAsBytes(GlutenConfig.GLUTEN_OFFHEAP_SIZE_KEY)
+ var onHeapSize: Long =
+ if (conf.contains(GlutenConfig.GLUTEN_ONHEAP_SIZE_KEY)) {
+ conf.getSizeAsBytes(GlutenConfig.GLUTEN_ONHEAP_SIZE_KEY)
+ } else {
+ // 1GB default
+ 1024 * 1024 * 1024
+ }
+
+ // If dynamic off-heap sizing is enabled, the off-heap size is calculated
based on the on-heap
+ // size. Otherwise, the off-heap size is set to the value specified by the
user (if any).
+ // Note that this means that we will IGNORE the off-heap size specified by
the user if the
+ // dynamic off-heap feature is enabled.
+ var offHeapSize: Long =
+ if (conf.getBoolean(GlutenConfig.GLUTEN_DYNAMIC_OFFHEAP_SIZING_ENABLED,
false)) {
+ // Since when dynamic off-heap sizing is enabled, we commingle on-heap
+ // and off-heap memory, we set the off-heap size to the usable on-heap
size. We will
+ // size it with a memory fraction, which can be aggressively set, but
the default
+ // is using the same way that Spark sizes on-heap memory:
+ //
+ // spark.gluten.memory.dynamic.offHeap.sizing.memory.fraction *
+ // (spark.executor.memory - 300MB).
+ //
+ // We will be careful to use the same configuration settings as Spark
to ensure
+ // that we are sizing the off-heap memory in the same way as Spark
sizes on-heap memory.
+ // The 300MB value, unfortunately, is hard-coded in Spark code.
+ ((onHeapSize - (300 * 1024 * 1024)) *
+
conf.getDouble(GlutenConfig.GLUTEN_DYNAMIC_OFFHEAP_SIZING_MEMORY_FRACTION,
0.6d)).toLong
+ } else if (conf.contains(GlutenConfig.GLUTEN_OFFHEAP_SIZE_KEY)) {
+ // Optimistic off-heap sizes, assuming all storage memory can be
borrowed into execution
+ // memory pool, regardless of Spark option
spark.memory.storageFraction.
+ conf.getSizeAsBytes(GlutenConfig.GLUTEN_OFFHEAP_SIZE_KEY)
+ } else {
+ // Default Spark Value.
+ 0L
+ }
+
conf.set(GlutenConfig.GLUTEN_OFFHEAP_SIZE_IN_BYTES_KEY,
offHeapSize.toString)
+ conf.set(GlutenConfig.GLUTEN_OFFHEAP_SIZE_KEY, offHeapSize.toString)
+
val offHeapPerTask = offHeapSize / taskSlots
conf.set(GlutenConfig.GLUTEN_TASK_OFFHEAP_SIZE_IN_BYTES_KEY,
offHeapPerTask.toString)
- // Pessimistic off-heap sizes, with the assumption that all non-borrowable
storage memory
- // determined by spark.memory.storageFraction was used.
- val fraction = 1.0d - conf.getDouble("spark.memory.storageFraction", 0.5d)
- val conservativeOffHeapPerTask = (offHeapSize * fraction).toLong /
taskSlots
- conf.set(
- GlutenConfig.GLUTEN_CONSERVATIVE_TASK_OFFHEAP_SIZE_IN_BYTES_KEY,
- conservativeOffHeapPerTask.toString)
+ // If we are using dynamic off-heap sizing, we should also enable off-heap
memory
+ // officially.
+ if (conf.getBoolean(GlutenConfig.GLUTEN_DYNAMIC_OFFHEAP_SIZING_ENABLED,
false)) {
+ conf.set(GlutenConfig.GLUTEN_OFFHEAP_ENABLED, "true")
Review Comment:
@ulysses-you thank you for the explanation.
> if there is enough free onhep memory, then we can borrow(logical borrow)
it to offheap side and prevent the onheap memory to be allocated.
I got the core idea, but I dont understand why it can prevent the onheap
memory allocation totally, would you give more explanation? thank you!
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