handlebars.java
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jknack
Including partials is slow?
I'm using this library as it is wrapped in vertx's templating adapters, source repo here. I have a very simple template (shown below) that just includes another partial (~27k in size) in order to render a header. I did a small benchmark using ab -n1000 -c25 http://localhost:9090/ with one HTTP server instance using this library to render. Having to use the {{ > ... }} is much slower than inlining it (~40 rps vs ~1k rps). I realize that caching mostly solves this issue but the discrepancy seems very large to me.
I'm happy to explore solutions and go digging for how to optimize this. Thanks!
Template
<html>
<head>
</head>
{{> header }}
</html>
Include Directive
This is ApacheBench, Version 2.3 <$Revision: 1807734 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking localhost (be patient)
Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Completed 600 requests
Completed 700 requests
Completed 800 requests
Completed 900 requests
Completed 1000 requests
Finished 1000 requests
Server Software:
Server Hostname: localhost
Server Port: 9090
Document Path: /
Document Length: 27355 bytes
Concurrency Level: 25
Time taken for tests: 26.094 seconds
Complete requests: 1000
Failed requests: 0
Total transferred: 27422000 bytes
HTML transferred: 27355000 bytes
Requests per second: 38.32 [#/sec] (mean)
Time per request: 652.346 [ms] (mean)
Time per request: 26.094 [ms] (mean, across all concurrent requests)
Transfer rate: 1026.27 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.4 0 4
Processing: 42 644 57.7 644 785
Waiting: 42 644 57.8 644 785
Total: 46 644 57.5 645 786
Percentage of the requests served within a certain time (ms)
50% 645
66% 649
75% 653
80% 657
90% 678
95% 689
98% 761
99% 770
100% 786 (longest request)
No include directive
This is ApacheBench, Version 2.3 <$Revision: 1807734 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking localhost (be patient)
Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Completed 600 requests
Completed 700 requests
Completed 800 requests
Completed 900 requests
Completed 1000 requests
Finished 1000 requests
Server Software:
Server Hostname: localhost
Server Port: 9090
Document Path: /
Document Length: 48927 bytes
Concurrency Level: 25
Time taken for tests: 1.088 seconds
Complete requests: 1000
Failed requests: 0
Total transferred: 48994000 bytes
HTML transferred: 48927000 bytes
Requests per second: 918.78 [#/sec] (mean)
Time per request: 27.210 [ms] (mean)
Time per request: 1.088 [ms] (mean, across all concurrent requests)
Transfer rate: 43959.71 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.5 0 4
Processing: 6 27 74.7 13 502
Waiting: 6 27 74.7 13 502
Total: 7 27 75.1 13 503
Percentage of the requests served within a certain time (ms)
50% 13
66% 16
75% 18
80% 19
90% 23
95% 32
98% 487
99% 499
100% 503 (longest request)
JProfiler
In: https://github.com/jknack/handlebars.java/blob/1f6c48e606dc1303d1e92a0a0eaa94120eba64fd/handlebars/src/main/java/com/github/jknack/handlebars/internal/Text.java#L93
I think it's worth considering to not always create a new char array that is just of the length of the required size, but to expand the capacity to a multiple of 2 (see implementation of StringBuilder for details) and, therefore, save a lot of calls to System.arraycopy. Especially, as append gets invoked very often with shorter Strings. Further more I would suggest using a StringBuilder internally that handles all the low level details... 😃
I'm working on it in this branch, will make a PR when everything is ready + I want to write a test for the new char vector.
@mach-kernel did anything ever get pulled in? We're seeing slow speeds on partials as well, just wondering if there was a fix.
Hi, I have made an easy version using StringBuilder here: https://github.com/jknack/handlebars.java/pull/831 Needs a final test, but might help to move forward here.