[
https://issues.apache.org/jira/browse/HDFS-7276?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Tsz Wo Nicholas Sze updated HDFS-7276:
--------------------------------------
Attachment: h7276_20141027.patch
h7276_20141027.patch:
- Renames the conf key DFS_CLIENT_WRITE_MAX_PACKETS_KEY; see HDFS-7260.
- Adds a performance test for comparing
-# new byte[] without any limit,
-# new byte[] with synchronization and a count for imposing a limit; and
-# using ByteArrayManager.
It turns out that ByteArrayManager is slighter better.
- nAllocations=16384
{noformat}
arrayLength=65536, nThreads=256, nAllocations=16384, maxArrays=1024
NewByteArrayWithoutLimit: 3306
NewByteArrayWithLimit: 3314
UsingByteArrayManager: 3278
arrayLength=65536, nThreads=256, nAllocations=16384, maxArrays=4096
NewByteArrayWithoutLimit: 3320
NewByteArrayWithLimit: 3313
UsingByteArrayManager: 3284
arrayLength=65536, nThreads=256, nAllocations=16384, maxArrays=16384
NewByteArrayWithoutLimit: 3342
NewByteArrayWithLimit: 3339
UsingByteArrayManager: 3306
arrayLength=65536, nThreads=256, nAllocations=16384, maxArrays=65536
NewByteArrayWithoutLimit: 3324
NewByteArrayWithLimit: 3320
UsingByteArrayManager: 3297
arrayLength=65536, nThreads=256, nAllocations=16384, maxArrays=262144
NewByteArrayWithoutLimit: 3322
NewByteArrayWithLimit: 3323
UsingByteArrayManager: 3284
{noformat}
- nAllocations=32768
{noformat}
arrayLength=65536, nThreads=256, nAllocations=32768, maxArrays=1024
NewByteArrayWithoutLimit: 6608
NewByteArrayWithLimit: 6648
UsingByteArrayManager: 6580
arrayLength=65536, nThreads=256, nAllocations=32768, maxArrays=4096
NewByteArrayWithoutLimit: 6572
NewByteArrayWithLimit: 6538
UsingByteArrayManager: 6451
arrayLength=65536, nThreads=256, nAllocations=32768, maxArrays=16384
NewByteArrayWithoutLimit: 6623
NewByteArrayWithLimit: 6613
UsingByteArrayManager: 6485
arrayLength=65536, nThreads=256, nAllocations=32768, maxArrays=65536
NewByteArrayWithoutLimit: 6564
NewByteArrayWithLimit: 6610
UsingByteArrayManager: 6488
arrayLength=65536, nThreads=256, nAllocations=32768, maxArrays=262144
NewByteArrayWithoutLimit: 6547
NewByteArrayWithLimit: 6556
UsingByteArrayManager: 6464
{noformat}
> Limit the number of byte arrays used by DFSOutputStream
> -------------------------------------------------------
>
> Key: HDFS-7276
> URL: https://issues.apache.org/jira/browse/HDFS-7276
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs-client
> Reporter: Tsz Wo Nicholas Sze
> Assignee: Tsz Wo Nicholas Sze
> Attachments: h7276_20141021.patch, h7276_20141022.patch,
> h7276_20141023.patch, h7276_20141024.patch, h7276_20141027.patch
>
>
> When there are a lot of DFSOutputStream's writing concurrently, the number of
> outstanding packets could be large. The byte arrays created by those packets
> could occupy a lot of memory.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
