Useostime Question on Solaris

Does any one have any test/experience on the cost difference on setting USEOSTIME to 1? Bruce Simms Data Base Services TALX Corporation 2330 Ball Drive St. Louis, MO 63146 Phone (314) 214-7703 FAX (314) 983-3238 bsimms@talx.com

Bruce Simms wrote: > Does any one have any test/experience on the cost difference on setting > USEOSTIME to 1?> The cost is VERY low, Bruce. It was made an ONCONFIG parameter because way back when, SCO Xenix and some other UNIXes did not have an efficient system call to provide high resolution time data so it was costly on some platforms. Today all OSes that IDS runs on provide an efficient implementation of gettimeofday() (or the Windoze equivalent) which is the system call that IDS now uses on UNIX. It is VERY cheap. I used it to calculate the maximum resolution of gettimeofday() and therefore DATETIME YEAR TO FRACTION(5) on different platforms calling it in a tight loop up to 100 million times todetermine if there was any value to storing more than FRACTION(2) resolution. I'm going from memory here (and I posted the resolution results on CDI a few years ago), but on Solaris the resolution was ~1/300 seconds and the test program reported that an average of 300-500 calls to gettimeofday)() returned the same time value within the loop which also had to include the two integer value comparisons and possibly an if test. That makes the runtime cost of a call somewhere in the neighborhood of 1/150000 seconds on 1.2GHZ single core UltraSparc II (or III?) processors (24 IB) the last time I ran the test. Darned efficient I'd say. I can give you the source for the test program if you want it. Art S. Kagel Oninit > Bruce Simms > Data Base Services > TALX Corporation > 2330 Ball Drive > St. Louis, MO 63146 > > Phone (314) 214-7703 > FAX (314) 983-3238 > bsimms@talx.com > > ================================================================================ =========== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.oninit.com/home/disclaimer.php ================================================================================ ===========

Art, Thanks for all you do for Informix and I was looking as I knew you had something but had not been able to find it. Bruce Simms Data Base Services TALX Corporation 2330 Ball Drive St. Louis, MO 63146 Phone (314) 214-7703 FAX (314) 983-3238 bsimms@talx.com -----Original Message----- From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of Art S. Kagel (Oninit) Sent: Thursday, March 06, 2008 9:35 AM To: ids@iiug.org Subject: Re: Useostime Question on Solaris [11517] Bruce Simms wrote: > Does any one have any test/experience on the cost difference on setting > USEOSTIME to 1?> The cost is VERY low, Bruce. It was made an ONCONFIG parameter because way back when, SCO Xenix and some other UNIXes did not have an efficient system call to provide high resolution time data so it was costly on some platforms. Today all OSes that IDS runs on provide an efficient implementation of gettimeofday() (or the Windoze equivalent) which is the system call that IDS now uses on UNIX. It is VERY cheap. I used it to calculate the maximum resolution of gettimeofday() and therefore DATETIME YEAR TO FRACTION(5) on different platforms calling it in a tight loop up to 100 million times todetermine if there was any value to storing more than FRACTION(2) resolution. I'm going from memory here (and I posted the resolution results on CDI a few years ago), but on Solaris the resolution was ~1/300 seconds and the test program reported that an average of 300-500 calls to gettimeofday)() returned the same time value within the loop which also had to include the two integer value comparisons and possibly an if test. That makes the runtime cost of a call somewhere in the neighborhood of 1/150000 seconds on 1.2GHZ single core UltraSparc II (or III?) processors (24 IB) the last time I ran the test. Darned efficient I'd say. I can give you the source for the test program if you want it. Art S. Kagel Oninit > Bruce Simms > Data Base Services > TALX Corporation > 2330 Ball Drive > St. Louis, MO 63146 > > Phone (314) 214-7703 > FAX (314) 983-3238 > bsimms@talx.com > > ======================================================================== =================== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.oninit.com/home/disclaimer.php ======================================================================== =================== ************************************************************************ ******* Forum Note: Use "Reply" to post a response in the discussion forum. See you at the IIUG Informix 2008 Conference The Power Conference for Informix Professionals April 27 - 30, 2008 Marriott Overland Park (Kansas City), Kansas http://www.iiug.org/conf Registration Now Open!!

I tried just that thing this morning and I found that the number of inserts done over a particular time period were about the same. Walt Lowich Bruce Simms <BSimms@talx.com> wrote: Does any one have any test/experience on the cost difference on setting USEOSTIME to 1? Bruce Simms Data Base Services TALX Corporation 2330 Ball Drive St. Louis, MO 63146 Phone (314) 214-7703 FAX (314) 983-3238 bsimms@talx.com ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum. See you at the IIUG Informix 2008 Conference The Power Conference for Informix Professionals April 27 - 30, 2008 Marriott Overland Park (Kansas City), Kansas http://www.iiug.org/conf Registration Now Open!! --------------------------------- Looking for last minute shopping deals? Find them fast with Yahoo! Search.

On Thu, Mar 6, 2008 at 7:34 AM, Art S. Kagel (Oninit) <art@oninit.com> wrote: > Bruce Simms wrote: > > Does any one have any test/experience on the cost difference on setting > > USEOSTIME to 1?> > The cost is VERY low, Bruce. It was made an ONCONFIG parameter because > way back when, SCO Xenix and some other UNIXes did not have an efficient > system call to provide high resolution time data so it was costly on > some platforms. Today all OSes that IDS runs on provide an efficient > implementation of gettimeofday() (or the Windoze equivalent) which is > the system call that IDS now uses on UNIX. It is VERY cheap. > > I used it to calculate the maximum resolution of gettimeofday() and > therefore DATETIME YEAR TO FRACTION(5) on different platforms calling it > in a tight loop up to 100 million times todetermine if there was any > value to storing more than FRACTION(2) resolution. I'm going from > memory here (and I posted the resolution results on CDI a few years > ago), but on Solaris the resolution was ~1/300 seconds and the test > program reported that an average of 300-500 calls to gettimeofday)() > returned the same time value within the loop which also had to include > the two integer value comparisons and possibly an if test. That makes > the runtime cost of a call somewhere in the neighborhood of 1/150000 > seconds on 1.2GHZ single core UltraSparc II (or III?) processors (24 IB) > the last time I ran the test. Darned efficient I'd say. > > I can give you the source for the test program if you want it. Art's analysis of the raw performance of gettimeofday() is accurate - it is fast. It isn't a system call on Solaris; it is a direct read of some memory locations. You can compare the speed of getpid() - which is about the simplest system call - and gettimeofday() is way faster. However, when IDS calls gettimeofday(), it also has to do some post-processing of the data, and the way it does that post-processing is a lot more expensive than the simple gettimeofday() call. Thus, if you speak to Tech Support or R&D, they will tell you that USEOSTIME is expensive. Treat my comment with a large pinch of salt (because I only run toy systems), but: I run my systems with USEOSTIME 1 so I can get sub-second resolution out of CURRENT. The performance impact for me is negligible. If you are running a TPC benchmark and need to wring the utmost performance out of the system, then USEOSTIME 0 may make sense. But for most people most of the time, the difference is not measurable. -- Jonathan Leffler #include <disclaimer.h> Email: jleffler@earthlink.net, jleffler@us.ibm.com Guardian of DBD::Informix v2007.0914 -- http://dbi.perl.org/ NB: Please do not use this email for correspondence. I don't necessarily read it every week, even.