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https://issues.apache.org/jira/browse/STORM-297?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13991586#comment-13991586
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ASF GitHub Bot commented on STORM-297:
--------------------------------------
Github user clockfly commented on a diff in the pull request:
https://github.com/apache/incubator-storm/pull/103#discussion_r12362595
--- Diff:
storm-core/src/jvm/backtype/storm/messaging/netty/MessageDecoder.java ---
@@ -34,52 +37,78 @@
*/
protected Object decode(ChannelHandlerContext ctx, Channel channel,
ChannelBuffer buf) throws Exception {
// Make sure that we have received at least a short
- if (buf.readableBytes() < 2) {
+ long available = buf.readableBytes();
+ if (available < 2) {
//need more data
return null;
}
- // Mark the current buffer position before reading task/len field
- // because the whole frame might not be in the buffer yet.
- // We will reset the buffer position to the marked position if
- // there's not enough bytes in the buffer.
- buf.markReaderIndex();
-
- //read the short field
- short code = buf.readShort();
-
- //case 1: Control message
- ControlMessage ctrl_msg = ControlMessage.mkMessage(code);
- if (ctrl_msg != null) return ctrl_msg;
-
- //case 2: task Message
- short task = code;
-
- // Make sure that we have received at least an integer (length)
- if (buf.readableBytes() < 4) {
- //need more data
- buf.resetReaderIndex();
- return null;
- }
+ List<Object> ret = new ArrayList<Object>();
+
+ while (available >= 2) {
--- End diff --
while loop, try to decode as more messages as possible.
> Storm Performance cannot be scaled up by adding more CPU cores
> --------------------------------------------------------------
>
> Key: STORM-297
> URL: https://issues.apache.org/jira/browse/STORM-297
> Project: Apache Storm (Incubating)
> Issue Type: Bug
> Reporter: Sean Zhong
> Labels: Performance, netty
> Fix For: 0.9.2-incubating
>
> Attachments: Storm_performance_fix.pdf, storm_performance_fix.patch
>
>
> We cannot scale up the performance by adding more CPU cores and increasing
> parallelism.
> For a 2 layer topology Spout ---shuffle grouping--> bolt, when message size
> is small (around 100 bytes), we can find in the below picture that neither
> the CPU nor the network is saturated. When message size is 100 bytes, only
> 40% of CPU is used, only 18% of network is used, although we have a high
> parallelism (overall we have 144 executors)
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