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From: Eliot M. <mo...@cs...> - 2012-06-01 11:23:33
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On 6/1/2012 6:34 AM, 齐玉华 wrote: > Thanks for your detail account. In the manual the program degradation is relatively 5 times slower > than native execution with the "--tool=none" flag. And "valgrind --tool=none -q date" takes about > 0.370 seconds. Thus, i assume that the valgrind start time is no more than 0.370 seconds. But I am > confused to the following program degradation(~about 10 times): --tool=none still rewrites code and in effect emulates your cpu's semantics on your same cpu. This emulation will indeed slow things down quite a bit. You can kind of think of it as like a somewhat optimized interpreter for your machine -- but it is still at some level an interpreter. So, a 10x slowdown is *good*, not bad, given what is going on under the covers. Eliot Moss |