NetNews Usenet Archive 1993 #1/NN_1993_1.iso/spool/comp/sys/mac/programm/20989

Text File | 1993-01-08 | 1.6 KB | 37 lines

Newsgroups: comp.sys.mac.programmer
Path: sparky!uunet!paladin.american.edu!howland.reston.ans.net!zaphod.mps.ohio-state.edu!sdd.hp.com!spool.mu.edu!sol.ctr.columbia.edu!eff!world!siegel
From: [e-mail] (Rich Siegel)
Subject: Re: Why is new(p) so slow in THINK Pascal?
Message-ID: <[e-mail]>
Keywords: THINK Pascal, dynamic variables
Organization: GCC Technologies
References: <[e-mail]>
Date: Fri, 8 Jan 1993 14:58:43 GMT
Lines: 25

In article <[e-mail]> [e-mail] writes:
>In order to compare some sorting procedures for linked lists (implemented
>in THINK Pascal) I applied them to random lists of varying lengths.
>It turns out that the procedure new(p), which allocates storage for
>a dynamic variable pointed to by p, is extremely slow.  Does anyone
>know why?  New-ing a thousand items takes a noticeable time, new-ing
>10,000 items takes minutes (on my lowly SE/30).

New() for pointer variables simply calls NewPtr. With that many small
blocks, you're overloading the Memory Manager, which has to find space
low in the heap each time you call New. Under the circumstances, you
might want to think about an alternative storage strategy.

Starting with an initial free list of pointer blocks is OK, but you're
still hammering the Memory Manager - you might want to think about
allocating a single large chunk and using pieces of it as you need them.

R.


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Rich Siegel                              Internet: [e-mail]
Senior Software Engineer
GCC Technologies