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remm pushed a commit to branch master
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The following commit(s) were added to refs/heads/master by this push:
new 9116e05 Change NIO poller thread count default to 1
9116e05 is described below
commit 9116e05bd04099512312993a27f89b74689b142a
Author: remm <[email protected]>
AuthorDate: Fri Apr 19 11:25:10 2019 +0200
Change NIO poller thread count default to 1
I don't see the benefit of the weird default (which is basically always
2, and I don't understand why it is better than 1). Maybe it was useful
in the past. Given a socket is associated with a poller, if something
(somehow) goes wrong, then this would create a partially responsive
server which is not really better but makes problems harder to detect.
If I missed something, I am 100% ok to revert it (but I would be
interested in the performance study that says 2 is better than 1 here).
---
java/org/apache/tomcat/util/net/NioEndpoint.java | 10 +++++++---
webapps/docs/changelog.xml | 4 ++++
webapps/docs/config/http.xml | 2 +-
3 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/java/org/apache/tomcat/util/net/NioEndpoint.java
b/java/org/apache/tomcat/util/net/NioEndpoint.java
index e84a34f..0df2846 100644
--- a/java/org/apache/tomcat/util/net/NioEndpoint.java
+++ b/java/org/apache/tomcat/util/net/NioEndpoint.java
@@ -147,7 +147,7 @@ public class NioEndpoint extends
AbstractJsseEndpoint<NioChannel,SocketChannel>
/**
* Poller thread count.
*/
- private int pollerThreadCount =
Math.min(2,Runtime.getRuntime().availableProcessors());
+ private int pollerThreadCount = 1;
public void setPollerThreadCount(int pollerThreadCount) {
this.pollerThreadCount = pollerThreadCount; }
public int getPollerThreadCount() { return pollerThreadCount; }
@@ -166,8 +166,12 @@ public class NioEndpoint extends
AbstractJsseEndpoint<NioChannel,SocketChannel>
* @return The next poller in sequence
*/
public Poller getPoller0() {
- int idx = Math.abs(pollerRotater.incrementAndGet()) % pollers.length;
- return pollers[idx];
+ if (pollerThreadCount == 1) {
+ return pollers[0];
+ } else {
+ int idx = Math.abs(pollerRotater.incrementAndGet()) %
pollers.length;
+ return pollers[idx];
+ }
}
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index 9992f8a..34fcdee 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -109,6 +109,10 @@
When running on newer JREs that don't support SSLv2Hello, don't warn
that it is not available unless explicitly configured. (markt)
</fix>
+ <fix>
+ Change default value of <code>pollerThreadCount</code> of NIO
+ to <code>1</code>. (remm)
+ </fix>
</changelog>
</subsection>
</section>
diff --git a/webapps/docs/config/http.xml b/webapps/docs/config/http.xml
index 9e68e39..039335d 100644
--- a/webapps/docs/config/http.xml
+++ b/webapps/docs/config/http.xml
@@ -735,7 +735,7 @@
<attribute name="pollerThreadCount" required="false">
<p>(int)The number of threads to be used to run for the polling events.
- Default value is <code>1</code> per processor but not more than 2.<br/>
+ Default value is <code>1</code>.<br/>
When accepting a socket, the operating system holds a global lock. So
the benefit of
going above 2 threads diminishes rapidly. Having more than one thread
is for
system that need to accept connections very rapidly. However usually
just
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