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https://issues.apache.org/jira/browse/TAP5-2332?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14128205#comment-14128205
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Jochen Kemnade edited comment on TAP5-2332 at 9/10/14 8:05 AM:
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{quote}
... but I really hope that just because you've found that String.format(...) is
slower than concatenation you don't stop using it
{quote}
Sure I will, at least for concatenation. Concatenation with {{+}} is more
readable *and* faster. I still prefer explicit {{StringBuilder}} usage though.
was (Author: jkemnade):
{qoute}
... but I really hope that just because you've found that String.format(...) is
slower than concatenation you don't stop using it
{quote}
Sure I will, at least for concatenation. Concatenation with {{+}} is more
readable *and* faster. I still prefer explicit {{StringBuilder}} usage though.
> Optimize String concatenation performance
> -----------------------------------------
>
> Key: TAP5-2332
> URL: https://issues.apache.org/jira/browse/TAP5-2332
> Project: Tapestry 5
> Issue Type: Improvement
> Reporter: Michael Mikhulya
> Priority: Minor
> Labels: patch, performance
> Attachments:
> 0001-TAP5-2332-Add-a-method-for-optimized-String-concaten.patch,
> 0001-TAP5-2332-Replace-String.format-call-by-simple-Strin.patch,
> 0001-TAP5-2332-get-rid-of-String.format-usage.patch, profile-patched.png,
> profile-vanilla.png
>
>
> During profiling I found that String.format provides much load on CPU.
> In many cases in Tapestry String.format can be easily replaced with simple
> String concatenation.
> Simple JMH (http://openjdk.java.net/projects/code-tools/jmh/) test
> {code:java}
> public class FormatVsConcat {
> private static final String format = "This is a test string with %s";
> private static final String concat1 = "This is a test string with ";
> private static final String concat2 = "test word";
> @GenerateMicroBenchmark
> public String format() {
> return String.format(format, concat2);
> }
> @GenerateMicroBenchmark
> public String concat() {
> return concat1 + concat2;
> }
> }
> {code}
> shows, that concatenation is 366(!) times faster.
> I removed only hot places in tapestry and get following results with apache
> benchmark:
> *Not patched* tapestry version:
> Requests per second: *21.38 /sec* (mean)
> Time per request: *46.764 [ms]* (mean)
> *Patched* tapestry version:
> Requests per second: *27.77 /sec* (mean)
> Time per request: *36.013 [ms]* (mean)
> So we gained 10ms per request or 20% of rendering time.
> If you don't mind I would like to get rid of String.format in all places of
> Tapestry and provide patch. I fixed only hot places which appeared during
> ab-profiling of one concrete page. So it is very likely that not all hot
> places were found and fixed.
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