Hi Joel, ----- Original Message ----- From: "joel falcou" <joel.falcou@lri.fr> To: <boost@lists.boost.org> Sent: Wednesday, January 20, 2010 11:05 PM Subject: Re: [boost] [chrono] v0.3.1 Support for wide characters
I kinda missed the last shot of comments but I have a question. You speak about:
* stopwatch_accumulator, capturing cummulated elapsed Clock times.
Do they use boost::accumulators and if yes, can we give them special stats to compute in addition to min,max,mean ?
Yes, it uses boost::accumulators so you can give it the Accumulator you want and of course define the associated formatter. I have not included an example on the documentation, but you can have an idea by looking on how stopwatch_accumulator is done and how the default accumulators is given. Here follow an example not yet compiled: #include <boost/chrono/stopwatches.hpp> #include <cmath> using namespace boost::chrono; using namespace boost::accumulators; typedef stopwatch_accumulator<process_real_cpu_clock, accumulator_set<process_real_cpu_clock::rep, features< tag::count, tag::sum, tag::min, tag::max, tag::mean > >, my_stopwatch_accumulator_formatter
::reporter my_stopwatch_accumulator_reporter;
// where my_stopwatch_accumulator_formatter will follow the same schema that stopwatch_accumulator_formatter.hpp int f1(long j) { static my_stopwatch_accumulator_reporter acc(BOOST_CHRONO_ACCUMULATOR_FUNCTION_FORMAT); my_stopwatch_accumulator_reporter::scoped_run _(acc); for ( long i = 0; i < j; ++i ) std::sqrt( 123.456L ); // burn some time return 0; } int main() { f1(100000); f1(200000); f1(300000); return 0; }
Other questions: is there plan for a cycle counter absed watch using the various compiler/os specific stuff like rdtsc et al ?
I'm sorry, but I suspect that I'm not competent in this domain. A clock don't require too much things. Thus for some one with a good knowledge of what is "a cycle counter absed watch using the various compiler/os specific stuff like rdtsc et al" it should be quite easy to implement a clock based on this counting. Here follows an extract from the documentation: A clock represents a bundle consisting of a native duration, a native time_point, and a function now() to get the current time_point. A clock must meet the requirements in the following Table. In this table C1 and C2 denote clock types. t1 and t2 are values returned from C1::now() where the call returning t1 happens before the call returning t2 and both of these calls happen before C1::time_point::max(). Table 1. Clock Requirements expression return type operational semantics C1::rep An arithmetic type or class emulating an arithmetic type. The representation type of the native duration and time_point. C1::period ratio The tick period of the clock in seconds. C1::duration chrono::duration<C1::rep, C1::period> The native duration type of the clock. C1::time_point chrono::time_point<C1> or chrono::time_point<C2, C1::duration> The native time_point type of the clock. Different clocks are permitted to share a time_point definition if it is valid to compare their time_points by comparing their respective durations. C1 and C2 must refer to the same epoch. C1::is_monotonic const bool true if t1 <= t2 is always true, else false. Note: A clock that can be adjusted backwards is not monotonic C1::now() C1::time_point Returns a time_point representing the current point in time. You could find a better formmating on the documentation. As you can see, you need just to implement a static function returning this counter. The rest is pure formalism. Hoping this answer your questions. Vicente