OSTIME PARAMETER
Hi Gurus: Activate the OSTIME parameter (1) On your expertise, What is the % slowed down of performance system ?? Thank in advance Juan Valeriano Villegas DBA
According to John Miller III, most modern UNIXes perform the gettimeofday function quickly and efficiently so there is no longer any appreciable overhead to turning OSTIME on. There were problems in the past with OSes like SCO XENIX/UNIX which is why the option to turn it off exists and is the default, however, currently popular UNIXes like AIX, HPUX, Solaris and Linux are fine. It's easy enough to test, just call gettimeofday() in a tight loop a few hundred times and see a) how long it takes by comparing the first call to the last, and b) how much/little system time is consumed by running the test under timex. In running a similar test app to determine the resolution of gettimeofday() on various OS/hardware platforms for our own apps I found that the resolution on Solaris was from 10-13 microseconds and that from 1 to 9 calls to gettimeofday() can be made within those 10-13 microseconds. On AIX the resolution is between 14 & 15 microseconds but you only get one call to gettimeofday in that span so it is a bit slower there. Haven't tried it on Linux at all. Let me know if you want the test code. Art S. Kagel ----- Original Message ----- From: Valeriano Villegas Juan <ids@iiug.org> At: 8/18 11:01:35 Hi Gurus: Activate the OSTIME parameter (1) On your expertise, What is the % slowed down of performance system ?? Thank in advance Juan Valeriano Villegas DBA ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum.
Art: Thanks for yor help, thanks for sharing your knowledge and please, send to me the test code I have HPUX 11.11 Regards -----Mensaje original----- De: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] En nombre de ART KAGEL, BLOOMBERG/ 731 LEXIN Enviado el: Viernes, 18 de Agosto de 2006 12:11 p.m. Para: ids@iiug.org Asunto: Re: OSTIME PARAMETER [7303] According to John Miller III, most modern UNIXes perform the gettimeofday function quickly and efficiently so there is no longer any appreciable overhead to turning OSTIME on. There were problems in the past with OSes like SCO XENIX/UNIX which is why the option to turn it off exists and is the default, however, currently popular UNIXes like AIX, HPUX, Solaris and Linux are fine. It's easy enough to test, just call gettimeofday() in a tight loop a few hundred times and see a) how long it takes by comparing the first call to the last, and b) how much/little system time is consumed by running the test under timex. In running a similar test app to determine the resolution of gettimeofday() on various OS/hardware platforms for our own apps I found that the resolution on Solaris was from 10-13 microseconds and that from 1 to 9 calls to gettimeofday() can be made within those 10-13 microseconds. On AIX the resolution is between 14 & 15 microseconds but you only get one call to gettimeofday in that span so it is a bit slower there. Haven't tried it on Linux at all. Let me know if you want the test code. Art S. Kagel ----- Original Message ----- From: Valeriano Villegas Juan <ids@iiug.org> At: 8/18 11:01:35 Hi Gurus: Activate the OSTIME parameter (1) On your expertise, What is the % slowed down of performance system ?? Thank in advance Juan Valeriano Villegas DBA ************************************************************************ ******* Forum Note: Use "Reply" to post a response in the discussion forum. ************************************************************************ ******* Forum Note: Use "Reply" to post a response in the discussion forum.
----- Original Message ----- From: Valeriano Villegas Juan <ids@iiug.org> At: 8/18 13:29:02 Art: Thanks for yor help, thanks for sharing your knowledge and please, send to me the test code I have HPUX 11.11 HPUX is a BSD based UNIX like AIX so the results will likely be similar to those from AIX, but that will also depend on your hardware. I tested HPUX/Itanium a couple of years ago and it was quick. Don't know that the PA-RISC is fast or not. Don't want to eat the bandwidth to post the code here since it generates hundreds of emails. Send me a private email (even a temp drop) and I'll send it to you directly. Art S. Kagel
Nada! Nothing! No-Penalties! It allowed us to have fractions of seconds in current. J. -----Original Message----- From: "Valeriano Villegas Juan" <jvaleriano@ref.pemex.com> To: ids@iiug.org Date: Fri, 18 Aug 2006 10:56:03 -0400 (EDT) Subject: OSTIME PARAMETER [7301] Hi Gurus: Activate the OSTIME parameter (1) On your expertise, What is the % slowed down of performance system ?? Thank in advance Juan Valeriano Villegas DBA ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum. Jean Sagi jeansagi@myrealbox.com jeansagi@gmail.com