I think you are spreading a myth about locking, Godfrey. It's not the addition of locks themselves that cause a performance penalty, after all, they result in a nop on a up system. The gratuitous adding of locks without regard to design (this is what lm complains about often) does add maintainence problems, but that is a matter of design not performance. The only performance penalty to making a system scale in number of cpus is when you have to make tradeoffs in the design of structures and algorithms. Usually you can (with a little more thought) find a design that will help both small system performance and large system performance... But sometimes that isn't possible. In those cases you could split and maintain two separate subsystems for the two designs but this again introduces maintainence headaches. Luckily we haven't gotten to that point yet... And I honestly don't know whether it will be worth it to pursue. (I'm making the assumption that we can scale into the 10's of processors without hitting that point.)
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I think you are spreading a myth about locking, Godfrey. It's not the addition of locks themselves that cause a performance penalty, after all, they result in a nop on a up system. The gratuitous adding of locks without regard to design (this is what lm complains about often) does add maintainence problems, but that is a matter of design not performance. The only performance penalty to making a system scale in number of cpus is when you have to make tradeoffs in the design of structures and algorithms. Usually you can (with a little more thought) find a design that will help both small system performance and large system performance... But sometimes that isn't possible. In those cases you could split and maintain two separate subsystems for the two designs but this again introduces maintainence headaches. Luckily we haven't gotten to that point yet... And I honestly don't know whether it will be worth it to pursue. (I'm making the assumption that we can scale into the 10's of processors without hitting that point.)
I really like the new features... Makes browsing the comments bearable.
Thanks Rob!