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Date: Thu, 22 Jul 2010 13:07:25 +0800
Message-ID: <AANLkTi=ELxFRa-ZE=gakM-SJPPZD2ynhKKSK2x0Cx61p@mail.gmail.com>
Subject: Security Performance issue
From: Ray Chen <clraychen@gmail.com>
To: dev@harmony.apache.org
Content-Type: text/plain; charset=ISO-8859-1

Hi All,
I found that our security implementation is much slower than RI's when
get an algorithm instance.
I have done some investigation and found that most time are consumed
on loading and initialising providers.
Following is the test cases and results to show this problem.

                      RI5         |      RI6      |     Harmony5    |
  Harmony6
Testcase1[1]    78ms      | 90~100ms  |     450ms        |   475~490ms
Testcase2[2]    75ms      |  85~91ms  |                       |
Testcase3[3]                  |                 |   447~455ms    | 470~490ms
Testcase4[4]    9~10ms  |   6ms         |                       |
Testcase5[5]                 |                  |    448~462ms   |  479~501ms
Testcase6[6]    9ms       |    8~10ms   |   448~459ms   |   481~490ms

From[1], we can see our implementation is much slower than RI's when
loading all the providers.
Compare [2] & [3], both loading JSSE provider, our implementation is
much slower.
Compare [2] & [4], the time differs, which means RI can load providers
one by one.
Compare [1],[3] & [5], we can see our implementation consumes almost
same time whether it loads one or more providers.
Form[6], I guess RI knows what services a provider provides so that it
can just pick up the providers the application need.

If you look into the Services.java, you will find that our
implementation will load all the providers when this class is loaded
even this application does NOT need some of providers.
Then it put all the providers and services into a cache which can be
called "pre-loading".

Base on the above investigation, I suggest to change the "pre-loading"
to "lazy-loading" if possible which means only loading necessary
providers, no more, no less.

But I found that it is very hard to achieve this target, because we
don't know what services a provider provides before we load the
provider.
I don't know what RI does to achieve this.
Maybe we can store the map relationships between these default
providers and services to a file or internal cache table?

Any comments or suggestions?

Jimmy, Kevin,
I talked to you about this issue before, feel free to fix me if
anything is wrong.
Or you can give more information about this issue.

[1]
public static void main(String[] args) {
        long start = System.currentTimeMillis();
        for (Provider p : Security.getProviders()) {
            p.getServices();
        }
        System.out.println(System.currentTimeMillis() - start);
}

[2]
public static void main(String[] args) throws NoSuchAlgorithmException {
    long start = System.currentTimeMillis();
    Security.getProvider("SUNJSSE");
    System.out.println(System.currentTimeMillis() - start);
}

[3]
public static void main(String[] args) throws NoSuchAlgorithmException {
     long start = System.currentTimeMillis();
     Security.getProvider("HarmonyJSSE");
     System.out.println(System.currentTimeMillis() - start);
}

[4]
public static void main(String[] args) throws NoSuchAlgorithmException {
        long start = System.currentTimeMillis();
        Security.getProvider("SUN");
        System.out.println(System.currentTimeMillis() - start);
}

[5]
public static void main(String[] args) throws NoSuchAlgorithmException {
    long start = System.currentTimeMillis();
    Security.getProvider("BC");
    System.out.println(System.currentTimeMillis() - start);
}

[6]
public static void main(String[] args) throws NoSuchAlgorithmException {
    long start = System.currentTimeMillis();
    MessageDigest.getInstance("SHA-1");
    System.out.println(System.currentTimeMillis() - start);
}
-- 
Regards,

Ray Chen