[Pki-devel] [PATCH] 4 Replaced byte-to-char & char-to-byte converters.

[Adam Young]

If the only questions are those of performance,  than it is a non issue 
for now.



On 12/20/2011 09:19 PM, Matthew Harmsen wrote:
> On 12/16/11 17:24, Endi Sukma Dewata wrote:
>> On 12/13/2011 4:25 PM, Adam Young wrote:
>>> On 12/13/2011 02:03 PM, Andrew Wnuk wrote:
>>>> Hopefully this patch was extremely well tested since it touches ASN.1
>>>> encoding.
>>> Do you have a specific set of tests that we should be running?
>>
>> I just posted patch #5 which contains some unit tests for the 
>> converters. I've also updated and split patch #4 into #4-2a (renaming 
>> the files) and #4-2b (replacing the implementation).
>>
>> Patch #5 should be applied before #4-2a/b to make sure there's no 
>> regression.
>>
>> Mozilla JSS library also has some ASN.1 code, should we use them to 
>> implement the converters?
>>
>> http://mxr.mozilla.org/mozilla/source/security/jss/org/mozilla/jss/asn1/
>>
>>
>>
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> Endi,
>
> Andrew and I have been looking at these changes, and we have the 
> following concerns:
>
> (1) First of all, we looked up the bug where some of the sun.io.* 
> classes were deprecated (which mentions java.nio.charset and sun.nio.cs):
>
>   * http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4948149
>
> (2) There appears to be considerable concern on performance 
> degradation when using "Charset":
>
>   * http://stackoverflow.com/questions/2098137/fast-alternative-to-java-nio-charset-charset-decode-encode
>   * http://www.theserverside.com/discussions/thread.tss?thread_id=61270
>


The article also states that the issue is being delat with in Java 7.  
We are standardizing on Java 7 for this release,  so it should not be an 
issue.

> (3) Additionally, there have been alterations in the CS code in the 
> past to fix problems encountered with the sun.io.* classes:
>
>   * pki/base/util/src/netscape/security/util/ByteToCharPrintable.java
>
> Although we have not gotten to the unit tests, we suspect that these 
> will be great to have regardless of the direction that is decided 
> upon.  However, due to our concerns regarding performance, could we 
> have some tests added (unit or a test tool) which obtain performance 
> results for the existing methods versus the proposed newer methods?
>
> If no discernable performance issues are encountered, most of these 
> changes appear to be acceptable -- the questionable one being the 
> replacing of the code that addressed issue (3) above.
>
> If there is an unacceptable degradation in performance, perhaps we 
> could utilize some customized Java classes to perform these functions. 
> As an alternative approach, as Endi alluded to, there is some ASN.1 
> code in Mozilla JSS, and speaking with Bob Relyea, we have been 
> postulating on how much work would be involved to write JNI bindings 
> via JSS to the ASN.1 encoders/decoders contained in NSS instead of 
> moving this code to use java.nio.* classes.  Theoretically, we may 
> limit our performance issues in exchange for the extra work involved 
> in making the effort to standardize on the NSS ASN.1 engine (although 
> I don't know if this will resolve issues such as (3) noted above).
>
> -- Matt

I am not worried about performance at this point,  it is way too 
premature.  I am only concerned with correctness.  The deprecated 
classes are going away, and we need an alternative to them.  We will 
have a deliberate performance and tuning iteration once the code base 
has been restructured.  If we find at that stage that there are still 
performance issues, we can look into writing a custom tuned solution, 
but based on overall system performance.


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