Proposed modifications to replay cache to prevent false positives

Ken Raeburn raeburn at MIT.EDU
Thu May 22 14:48:44 EDT 2008


On May 20, 2008, at 18:48, Nicolas Williams wrote:
> Will profiled the code and found unnecessary gettimeofday() syscalls  
> in
> the main loop

Are we talking about something along the lines of http://isda-maven1.mit.edu:8060/changelog/krb5/?cs=15799 
  or something on top of that?

> and function calls in the main loop which when turned to
> macros greatly reduce overhead.

I'm inclined to say that an optimizing compiler should just DTRT.   
Though in our default configuration, the configure script wouldn't  
normally turn on optimization for Sun's compiler...  (Historically,  
some compilers have had trouble with using both -g and -O, and so  
autoconf normally gives you just -g if you're not using gcc.)

If it's still a problem, we can look at making functions explicitly  
inline, or converting them to macros.  But we should confirm that it's  
(still) a problem, first.

>>> - provide an option to set the server-side skew to some number of
>>> seconds, which in general should be estimated time to boot * 2
>>
>> [libdefaults]->clockskew is used (and defaults to 300s)
>
> Yes, yes.  I'd like that to be somewhat more automatic.  One boolean  
> in
> the config, instead of a numeric.

And the Kerberos library should magically know how long it takes the  
machine to boot, and use that value?  That's going to vary a lot  
depending on operating system, cpu, file system configuration, etc.

Ken



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