Dear all,
this is my first mail to the list, so first I wanted to say hello and kindly ask you for forgiveness if I break any conventions that usually apply in the list.
We were doing some program performance testing with Poly ML 5.5 and we detected the following behavior when trying to use the information provided by "PolyML.timing" (I tried to produce a toy example).
fun fact (n : int) = (if n = 0 then 1 else n * fact (n -1 )); PolyML.timing true; open TextIO; val foo = openOut ("foo"); open Int; output (foo, toString (fact (10000)));
The last function returns a "run" time of "0.1" in a Linux machine, but "11.7" (approx) in our Windows machine, when the real time can be checked in both machines to be of the order of "0.1" (actually, the Windows machine in our case has much better hardware and is indeed faster in computations, this is the reason why we wanted to stick to it). Somehow, the timing information provided in the Windows machine is not correct. It scales to greater computations, where 200 seconds of real run time are shown in Windows as maybe 2000.
In our Linux machine we have used the polyml version shipped with Isabelle 2013, whereas in the Windows machine we are using the binary version for Windows obtained from sourceforge.
Are we doing anything wrong? Is this a known issue?
Thanks for any hints,
Jesus
-- Jes?s Mar?a Aransay Azofra Universidad de La Rioja Dpto. de Matem?ticas y Computaci?n tlf.: (+34) 941299438 fax: (+34) 941299460 mail: jesus-maria.aransay at unirioja.es ; web: http://www.unirioja.es/cu/jearansa Edificio Luis Vives, c/ Luis de Ulloa s/n, 26004 Logro?o, Espa?a
Hi Jesus,
On 21/05/2013 19:31, Jesus Aransay wrote:
this is my first mail to the list, so first I wanted to say hello and kindly ask you for forgiveness if I break any conventions that usually apply in the list.
Welcome to the list. It has a very low posting rate so we don't need to worry about conventions.
We were doing some program performance testing with Poly ML 5.5 and we detected the following behavior when trying to use the information
The last function returns a "run" time of "0.1" in a Linux machine, but "11.7" (approx) in our Windows machine, when the real time can be checked in both machines to be of the order of "0.1" (actually, the Windows machine in our case has much better hardware and is indeed faster in computations, this is the reason why we wanted to stick to it). Somehow, the timing information provided in the Windows machine is not correct. It scales to greater computations, where 200 seconds of real run time are shown in Windows as maybe 2000.
In our Linux machine we have used the polyml version shipped with Isabelle 2013, whereas in the Windows machine we are using the binary version for Windows obtained from sourceforge.
Are we doing anything wrong? Is this a known issue?
I would guess that you're using PolyML.timing for the timing. I discovered a bug in the way it worked on Windows and fixed it in SVN. Perhaps the easiest way to work-around it is to use the functions from the Timer structure (startCPUTimer and checkCPUTimes) and then wrap the function you want to time in calls to them. They should work correctly on both Windows and Linux. If there are any problems let me know.
David
Dear David,
thanks for your answer;
On Wed, May 22, 2013 at 10:01 AM, David Matthews <David.Matthews at prolingua.co.uk> wrote:
Hi Jesus,
On 21/05/2013 19:31, Jesus Aransay wrote:
this is my first mail to the list, so first I wanted to say hello and kindly ask you for forgiveness if I break any conventions that usually apply in the list.
Welcome to the list. It has a very low posting rate so we don't need to worry about conventions.
I did not add a subject to my mail (my mail client neither warned me), so I think this is the first list convention I unintentionally broke, sorry for that.
I would guess that you're using PolyML.timing for the timing. I discovered a bug in the way it worked on Windows and fixed it in SVN. Perhaps the easiest way to work-around it is to use the functions from the Timer structure (startCPUTimer and checkCPUTimes) and then wrap the function you want to time in calls to them. They should work correctly on both Windows and Linux. If there are any problems let me know.
You were right, we were using PolyML.timing. We now applied the Timer structure, and we realized that, at least in some examples, the times we obtain with PolyML.timing are exactly the times provided by the Timer functions startCPUTimer and checkCPUTimes multiplied by 10. We will stick to the Timer structure timings.
Thanks for your quick reply and support,
Jesus
David
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jesus-maria.aransay＠unirioja.es