From: erik quanstrom <quanstro@coraid.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] slow performance
Date: Sat, 31 Mar 2007 21:32:17 -0400 [thread overview]
Message-ID: <798e803ad46d7e986daedaa82d5ec9bf@coraid.com> (raw)
In-Reply-To: <e510e47e0703311625sbc2646ay1aa80271fcd380a6@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 779 bytes --]
when you compiled this on plan 9, you must have
either replaced stdlib.h with something else or have used
ape. i substituted libbio and get almost the same performance
you did on linux. i used my home cpu server, a amd64 revF 3800+.
cpu% 8c -FVw t.c
warning: t.c:64 set and not used: t
cpu% 8l -o t t.8
cpu% time t >/tmp/xyzw
2.08u 0.05s 2.36r t
i think the reason for the difference in performance is that somehow
your translation of print was calling write(2) for each integer printed.
assuming i understand the point of this program -- sorting a bunch of
integers, i rewrote this program using an array and qsort, which should
be more memory efficient and faster. here's what i get
cpu% time ./u >/tmp/xyz
0.08u 0.01s 0.22r ./u
- erik
[-- Attachment #2: t.c --]
[-- Type: text/plain, Size: 831 bytes --]
#include <u.h>
#include <libc.h>
#include <bio.h>
enum{
MAX = 200000,
};
typedef struct Bst Bst;
struct Bst{
int v;
Bst *menor;
Bst *maior;
};
Biobuf b;
Bst*
pbst(Bst *t)
{
if(t->menor != 0)
t->menor = pbst(t->menor);
Bprint(&b, "%d - ", t->v);
if(t->maior != 0)
t->maior = pbst(t->maior);
return t;
}
Bst*
bstini(int v)
{
Bst *t;
t = malloc(sizeof *t);
t->v = v;
t->maior = 0;
t->menor = 0;
return t;
}
Bst *
bstadd(int v, Bst *t)
{
if(t == 0)
t = bstini(v);
else if(v >= t->v)
t->maior = bstadd(v, t->maior);
else
t->menor = bstadd(v, t->menor);
return t;
}
void
main(void)
{
Bst *t;
int i;
Binit(&b, 1, OWRITE);
t = 0;
srand(time(0));
for(i = 0; i < MAX; i++)
t = bstadd(rand()%1000, t);
t = pbst(t);
exits("");
}
[-- Attachment #3: u.c --]
[-- Type: text/plain, Size: 435 bytes --]
#include <u.h>
#include <libc.h>
#include <bio.h>
enum{
MAX = 200000,
};
int
intcmp(void *a, void *b)
{
return *((int*)a)-*((int*)b);
}
void
main(void)
{
Biobuf b;
int *t, i;
Binit(&b, 1, OWRITE);
t = malloc(MAX*sizeof *t);
srand(time(0));
for(i = 0; i < MAX; i++)
t[i] = rand()%1000;
qsort(t, MAX, sizeof *t, intcmp);
for(i = 0; i < MAX; i++)
Bprint(&b, " - %d", t[i]);
exits("");
}
next prev parent reply other threads:[~2007-04-01 1:32 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-31 16:41 pedro henrique antunes de oliveira
2007-03-31 16:48 ` Lorenzo Fernando Bivens de la Fuente
2007-03-31 16:48 ` Charles Forsyth
2007-03-31 16:57 ` pedro henrique antunes de oliveira
2007-03-31 16:55 ` W B Hacker
2007-03-31 17:12 ` Uriel
2007-03-31 19:27 ` W B Hacker
2007-03-31 23:20 ` erik quanstrom
2007-03-31 23:35 ` pedro henrique antunes de oliveira
2007-04-01 1:40 ` erik quanstrom
2007-03-31 17:15 ` Charles Forsyth
2007-03-31 18:50 ` Armando Camarero
2007-03-31 21:05 ` C H Forsyth
2007-03-31 23:25 ` pedro henrique antunes de oliveira
2007-04-01 1:32 ` erik quanstrom [this message]
2007-04-01 9:22 ` Charles Forsyth
2007-04-01 9:52 ` pedro henrique antunes de oliveira
2007-04-01 9:56 ` pedro henrique antunes de oliveira
2007-04-01 18:24 ` ron minnich
2007-04-01 19:11 ` pedro henrique antunes de oliveira
2007-04-01 19:26 ` geoff
2007-04-01 19:57 ` pedro henrique antunes de oliveira
2007-04-01 20:07 ` Charles Forsyth
2007-04-01 20:11 ` pedro henrique antunes de oliveira
2007-04-01 20:26 ` Charles Forsyth
2007-04-01 21:13 ` ISHWAR RATTAN
2007-04-02 1:52 ` pedro henrique antunes de oliveira
2007-04-01 12:08 erik quanstrom
2007-04-01 12:35 ` pedro henrique antunes de oliveira
2007-04-01 14:39 ` Uriel
2007-04-01 15:11 ` C H Forsyth
2007-04-01 17:35 ` pedro henrique antunes de oliveira
2007-04-01 18:05 ` erik quanstrom
2007-04-02 9:14 phao
2007-04-02 9:31 ` Anselm R. Garbe
2007-04-02 9:38 ` Charles Forsyth
2007-04-02 9:42 ` C H Forsyth
2007-04-02 9:45 ` Anselm R. Garbe
2007-04-02 12:49 ` pedro henrique antunes de oliveira
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