I think discussions on performance go south because we all instinctively use Big-Oh ideas, but there are times when constant multipliers really matter: when the computation is really, really long (big scientific computations), or when microseconds matter (interactivity and real time stuff).
As an example, for big scientific computations, Fortran seems to be about 30% faster than C, its next fastest competitor (at least this is what some physicists who did huge jobs to process imagery data to look for planets told me once). If you are running a job that takes 15 minutes in C, this doesn't matter, but if you are running a job that takes 10 days it matters immensely, especially when you consider that you still have to debug. 30% is three more days you have to wait for output before tweaking your stuff and trying to beat the other guys to publication.
With interactive programming, performance means you either get under the perceived instantaneous threshold or not, which is often the difference between "this app is cool" or "this app sucks". If you can get a 2 fold gain using C versus Java or C#, you can do a LOT of stuff "instantaneously" that otherwise make the user tap their fingers impatiently. Not too mention the high speed work of quants.
In the work I do -- processing moderately large datasets into summaries on 12 hour deadlines -- 20% here or there doesn't really matter. I think this is kind of interesting
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I think discussions on performance go south because we all instinctively use Big-Oh ideas, but there are times when constant multipliers really matter: when the computation is really, really long (big scientific computations), or when microseconds matter (interactivity and real time stuff).
As an example, for big scientific computations, Fortran seems to be about 30% faster than C, its next fastest competitor (at least this is what some physicists who did huge jobs to process imagery data to look for planets told me once). If you are running a job that takes 15 minutes in C, this doesn't matter, but if you are running a job that takes 10 days it matters immensely, especially when you consider that you still have to debug. 30% is three more days you have to wait for output before tweaking your stuff and trying to beat the other guys to publication.
With interactive programming, performance means you either get under the perceived instantaneous threshold or not, which is often the difference between "this app is cool" or "this app sucks". If you can get a 2 fold gain using C versus Java or C#, you can do a LOT of stuff "instantaneously" that otherwise make the user tap their fingers impatiently. Not too mention the high speed work of quants.
In the work I do -- processing moderately large datasets into summaries on 12 hour deadlines -- 20% here or there doesn't really matter. I think this is kind of interesting