On 1/12/2012 2:23 PM, John Gilmore wrote:
No one has ever claimed that the timing differences here are large, significant ones; and the continuing preoccupation here with suboptimizing of this sort is, I think, evidence of a pervasive malaise, a retreat into the familiar that precludes consideration of more, much more, important design issues.
In general I tend to agree with this, but I've worked or consulted at installations that either had problems completing overnight jobs in their assigned batch window, or just processing large amounts of data. While I haven't tried this on very current machines, on older ones EX added 40 to 50% to the instruction time (EX overhead on some Amdahl machines was greater); 4 MVCs of 256 bytes were about the same as a 1K MVCL; and 5 CLI/BE were about the same as one TRT/B *+4(R2). In each case if paid to identify the most frequently executed code and look for improvements. Gerhard Postpischil Bradford, VT
