On 28/01/2016 14:16, Konstantin Kolinko wrote: > 2016-01-28 17:04 GMT+03:00 <ma...@apache.org>: >> Author: markt >> Date: Thu Jan 28 14:04:00 2016 >> New Revision: 1727355 >> >> URL: http://svn.apache.org/viewvc?rev=1727355&view=rev >> Log: >> Switch OutputBuffer to a local Map of C2BConvertors. Loading testing with >> HTTP/2 and default Tomcat home page suggests an improvement of a few percent >> in throughput. > > How much memory is wasted?
I wouldn't call that memory 'wasted'. I'd call it 'used' to gain somewhere in the region of a 2% to 4% throughput increase. > Every connection (incl. keep-alive ones) will have its own map of > encoders? Encoders are not reused across different connections? Using the same load test as I used for the performance numbers, I see a retained size of less than 1MB all of which is eligible for GC. There isn't much reuse in HTTP/2. If I switch to HTTP/1.1 and run the same test I end up with ~60 instances using ~16k. Scale that up to 2000 concurrent connections and you get ~550k so I am not worried about memory use in this case. I didn't measure the performance gain of this change for HTTP/1.1 but I'd expect there to be some benefit although not as much as HTTP/2 simply because HTTP/2 uses more concurrency for broadly the same load. Mark > > >> Modified: >> tomcat/trunk/java/org/apache/catalina/connector/OutputBuffer.java >> >> Modified: tomcat/trunk/java/org/apache/catalina/connector/OutputBuffer.java >> URL: >> http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/catalina/connector/OutputBuffer.java?rev=1727355&r1=1727354&r2=1727355&view=diff >> ============================================================================== >> --- tomcat/trunk/java/org/apache/catalina/connector/OutputBuffer.java >> (original) >> +++ tomcat/trunk/java/org/apache/catalina/connector/OutputBuffer.java Thu >> Jan 28 14:04:00 2016 >> @@ -22,7 +22,8 @@ import java.nio.charset.Charset; >> import java.security.AccessController; >> import java.security.PrivilegedActionException; >> import java.security.PrivilegedExceptionAction; >> -import java.util.concurrent.ConcurrentHashMap; >> +import java.util.HashMap; >> +import java.util.Map; >> >> import javax.servlet.WriteListener; >> import javax.servlet.http.HttpServletResponse; >> @@ -34,7 +35,6 @@ import org.apache.tomcat.util.buf.B2CCon >> import org.apache.tomcat.util.buf.ByteChunk; >> import org.apache.tomcat.util.buf.C2BConverter; >> import org.apache.tomcat.util.buf.CharChunk; >> -import org.apache.tomcat.util.collections.SynchronizedStack; >> import org.apache.tomcat.util.res.StringManager; >> >> /** >> @@ -55,8 +55,7 @@ public class OutputBuffer extends Writer >> /** >> * Encoder cache. >> */ >> - private static final ConcurrentHashMap<Charset, >> SynchronizedStack<C2BConverter>> encoders = >> - new ConcurrentHashMap<>(); >> + private final Map<Charset, C2BConverter> encoders = new HashMap<>(); >> >> >> // ----------------------------------------------------- Instance >> Variables >> @@ -233,7 +232,6 @@ public class OutputBuffer extends Writer >> >> if (conv != null) { >> conv.recycle(); >> - encoders.get(conv.getCharset()).push(conv); >> conv = null; >> } >> >> @@ -560,16 +558,11 @@ public class OutputBuffer extends Writer >> } >> >> final Charset charset = getCharset(enc); >> - SynchronizedStack<C2BConverter> stack = encoders.get(charset); >> - if (stack == null) { >> - stack = new SynchronizedStack<>(); >> - encoders.putIfAbsent(charset, stack); >> - stack = encoders.get(charset); >> - } >> - conv = stack.pop(); >> + conv = encoders.get(charset); >> >> if (conv == null) { >> conv = createConverter(charset); >> + encoders.put(charset, conv); >> } >> } >> >> @@ -659,7 +652,6 @@ public class OutputBuffer extends Writer >> if (resetWriterStreamFlags) { >> if (conv != null) { >> conv.recycle(); >> - encoders.get(conv.getCharset()).push(conv); >> } >> conv = null; >> enc = null; >> >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org >> For additional commands, e-mail: dev-h...@tomcat.apache.org >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org > For additional commands, e-mail: dev-h...@tomcat.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For additional commands, e-mail: dev-h...@tomcat.apache.org
