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Groups > comp.lang.java.programmer > #33035
| From | Jerry Stuckle <jstucklex@attglobal.net> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Things have 'moved on' apparently |
| Date | 2015-11-08 21:32 -0500 |
| Organization | A noiseless patient Spider |
| Message-ID | <n1p0fs$h45$1@dont-email.me> (permalink) |
| References | (4 earlier) <da9gi0F6a6nU1@mid.individual.net> <n1ods3$bh2$1@dont-email.me> <n1ogvq$70k$1@speranza.aioe.org> <n1oljq$bda$1@dont-email.me> <n1oq1c$p1a$1@speranza.aioe.org> |
On 11/8/2015 7:40 PM, Arne Vajhøj wrote: > On 11/8/2015 6:24 PM, Martin Gregorie wrote: >> On Sun, 08 Nov 2015 17:05:47 -0500, Arne Vajhøj wrote: >> >>> On 11/8/2015 4:12 PM, Martin Gregorie wrote: >>>> In this case the offending functions were the malloc and B-tree modules >>>> in the C standard library for DEC's Alpha servers running TrueUNIX. >>>> >>>> The root problem was that the OS was Mach-based and the implementation >>>> seemed to use a single-threaded process to implement each low level >>>> clib function: at least, we found this problem in several parts of the >>>> OS. Maybe this is the main reason that Mach message-passing >>>> micro-kernel architectures have largely disappeared, but I digress... >>>> >>>> The effect was that, because the btree routine used three chunks of >>>> memory for each node (IIRC one for key, one for data, one for the three >>>> pointers), so that lookups (which added unknown nodes to the tree) >>>> bottle- >>>> necked on the malloc() process with three calls per node added. We >>>> needed something like 7,000 lookups/sec but couldn't break 800. >>>> >>>> So I rewrote the btree functions to use only one struct per node, which >>>> gave an immediate speedup to better than 1500 lookups/sec. >>>> >>>> More checks showed that now the sbrk() function that malloc() called >>>> each time it needed to extend process heap memory had the same problem. >>>> So, I changed my code to use malloc() to grab MB-sized chunks of heap >>>> space and and wrote an application level function that allocated btree >>>> nodes in my chunk of heap and asked for more when it was needed. This >>>> gave me 25,000 looks/sec: job done! >>> >>> Isn't that what __mingrow was supposed to do in a more transparent way? >>> >> 'locate' doesn't find __mingrow (or mingrow) in my development >> environment. The pnly references I can find are in relation to a C# >> priority queue: this all happened long before C# existed. > > http://www3.physnet.uni-hamburg.de/physnet/Tru64-Unix/HTML/MAN/MAN3/0892____.HTM > > > Arne > "Note that these variables and their effects are specific to the current DIGITAL UNIX memory allocation implementation." The variables are implementation specific, and may or may not exist in his library implementation. -- ================== Remove the "x" from my email address Jerry Stuckle jstucklex@attglobal.net ==================
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Things have 'moved on' apparently Eternal Hope <laughingspam99@gmail.com> - 2015-11-06 12:32 +0000
Re: Things have 'moved on' apparently Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2015-11-06 08:25 -0800
Re: Things have 'moved on' apparently Eric Douglas <e.d.programmer@gmail.com> - 2015-11-06 12:02 -0800
Re: Things have 'moved on' apparently Jerry Stuckle <jstucklex@attglobal.net> - 2015-11-06 19:46 -0500
Re: Things have 'moved on' apparently Martin Gregorie <martin@address-in-sig.invalid> - 2015-11-07 17:21 +0000
Re: Things have 'moved on' apparently Jerry Stuckle <jstucklex@attglobal.net> - 2015-11-07 12:50 -0500
Re: Things have 'moved on' apparently Eric Douglas <e.d.programmer@gmail.com> - 2015-11-09 05:37 -0800
Re: Things have 'moved on' apparently Jerry Stuckle <jstucklex@attglobal.net> - 2015-11-09 09:00 -0500
Re: Things have 'moved on' apparently Martin Gregorie <martin@address-in-sig.invalid> - 2015-11-09 14:56 +0000
Re: Things have 'moved on' apparently Martin Gregorie <martin@address-in-sig.invalid> - 2015-11-09 19:25 +0000
Re: Things have 'moved on' apparently Arne Vajhøj <arne@vajhoej.dk> - 2015-11-07 21:57 -0500
Re: Things have 'moved on' apparently Arne Vajhøj <arne@vajhoej.dk> - 2015-11-07 22:02 -0500
Re: Things have 'moved on' apparently leif.roar@dimnakorr.com - 2015-11-08 02:00 -0600
Re: Things have 'moved on' apparently Arne Vajhøj <arne@vajhoej.dk> - 2015-11-08 08:44 -0500
Re: Things have 'moved on' apparently leif.roar@dimnakorr.com - 2015-11-08 13:08 -0600
Re: Things have 'moved on' apparently Robert Klemme <shortcutter@googlemail.com> - 2015-11-08 18:54 +0100
Re: Things have 'moved on' apparently Martin Gregorie <martin@address-in-sig.invalid> - 2015-11-08 21:12 +0000
Re: Things have 'moved on' apparently Arne Vajhøj <arne@vajhoej.dk> - 2015-11-08 17:05 -0500
Re: Things have 'moved on' apparently Martin Gregorie <martin@address-in-sig.invalid> - 2015-11-08 23:24 +0000
Re: Things have 'moved on' apparently Arne Vajhøj <arne@vajhoej.dk> - 2015-11-08 19:40 -0500
Re: Things have 'moved on' apparently Jerry Stuckle <jstucklex@attglobal.net> - 2015-11-08 21:32 -0500
Re: Things have 'moved on' apparently Martin Gregorie <martin@address-in-sig.invalid> - 2015-11-09 15:15 +0000
Re: Things have 'moved on' apparently Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2015-11-08 12:10 -0800
Re: Things have 'moved on' apparently Jerry Stuckle <jstucklex@attglobal.net> - 2015-11-08 16:00 -0500
Re: Things have 'moved on' apparently Arne Vajhøj <arne@vajhoej.dk> - 2015-11-08 16:51 -0500
Re: Things have 'moved on' apparently Jan Burse <janburse@fastmail.fm> - 2015-11-08 00:55 +0100
Re: Things have 'moved on' apparently Arne Vajhøj <arne@vajhoej.dk> - 2015-11-07 21:28 -0500
Re: Things have 'moved on' apparently Arne Vajhøj <arne@vajhoej.dk> - 2015-11-07 21:36 -0500
Re: Things have 'moved on' apparently leif.roar@dimnakorr.com - 2015-11-08 02:12 -0600
Re: Things have 'moved on' apparently askfor <askfor@nowhere.net> - 2015-11-09 18:02 +0100
Re: Things have 'moved on' apparently Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2015-11-10 22:32 -0800
Re: Things have 'moved on' apparently Eternal Hope <laughingspam99@gmail.com> - 2015-11-11 07:52 +0000
Re: Things have 'moved on' apparently ross.finlayson@gmail.com - 2015-11-19 23:28 -0800
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