* [parisc-linux] [Kernel Hacker Challenge #1] Make my loop.c run faster, fly higher, and win big!
@ 2004-01-08 5:42 Carlos O'Donell
2004-01-09 13:56 ` [parisc-linux] [Kernel Hacker Challenge #1] loop.c source update Carlos O'Donell
0 siblings, 1 reply; 2+ messages in thread
From: Carlos O'Donell @ 2004-01-08 5:42 UTC (permalink / raw)
To: parisc-linux
pa,
============================================
UP PA8700 @650Mhz.
============================================
round 1
...
round 999
round 1000
real 0m1.559s
user 0m0.000s
sys 0m1.430s
Too slow joe! :)
============================================
UP PIII @450MHz
============================================
round 1
...
round 999
round 1000
real 0m0.303s
user 0m0.010s
sys 0m0.090s <- Look at that sys time!
*Fast*
============================================
Why is it so slow on hppa?
============================================
Profile reveals some hints:
161 total 0.0001
89 flush_user_dcache_range_asm 2.4722
48 flush_user_icache_range_asm 1.3333
8 pc_in_user_space 0.0667
2 zap_page_range 0.0016
2 __muldi3 0.0071
1 syscall_restore 0.0041
1 rmqueue 0.0007
1 normal_poll 0.0020
1 n_tty_receive_buf 0.0003
1 memset 0.0054
1 kmalloc 0.0023
1 get_unused_fd 0.0021
1 fget 0.0139
1 fdsync 0.0500
1 do_mmap_pgoff 0.0006
1 __down_read_trylock 0.0208
1 $lctu_loop 0.0833
---
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#define BUFLEN 512
#define PAGESIZE 4096
#define PAGEMASK 0x1888
/*
Sample trace of what glibc does during dlopen/dlclose pair ...
968 open("./tst-tlsmod13.so", O_RDONLY) = 3
969 read(3, "\177ELF\1\2\1\3\0\0\0\0\0\0\0\0\0\3\0\17\0\0\0\1\0\0\10"..., 512) = 512
970 fstat64(3, {st_mode=0, st_size=4294967297000, ...}) = 0
*NO*971 getcwd("/home/carlos/src/glibc-work/tests/tst-tls13", 128) = 44
972 mmap(NULL, 69232, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x401b2000
973 mprotect(0x401b3000, 65136, PROT_NONE) = 0
974 mmap(0x401c2000, 4096, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0x401c2000
975 close(3) = 0
*NO*976 munmap(0x401a1000, 69352) = 0
977 munmap(0x401b2000, 69232) = 0
Compile this code with:
gcc -o loop loop.c
Create the test file with:
dd if=/dev/zero of=./testdata bs=1024 count=70
*/
int
main (void)
{
int i;
char buffer[BUFLEN];
void * start = NULL;
int offset = 0;
void * end = NULL;
size_t length = 0;
int filefd;
void * filemap;
void * filemap2;
struct stat statbuf;
for (i = 0; i < 1000;)
{
printf ("round %d\n",++i);
/* File is 70 * 1024 bytes */
filefd = open("./testdata", O_RDONLY);
if (filefd == -1) { perror("open"); exit(1); }
/* Read 512 bytes into a buffer... or less */
length = read(filefd, buffer, BUFLEN);
if (length == 0) { perror("read"); exit(1); }
/* Find the real size */
if (fstat(filefd, &statbuf) != 0) { perror("fstat"); exit(1); }
length = statbuf.st_size;
/* mmap without protection */
filemap = mmap (start, length, PROT_READ|PROT_EXEC, MAP_PRIVATE, filefd, offset);
if (filemap == MAP_FAILED) { perror("mmap"); exit (1); }
/* Load in a page of zeros, starting at the next page */
filemap2 = mmap (start, PAGESIZE, PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_PRIVATE|MAP_FIXED, filefd, offset);
if ( filemap2 == MAP_FAILED ) { perror("mmap2"); exit(1); }
/* Protect everything but the first page */
start = (void *)(((unsigned int)(filemap) & ~PAGEMASK) + PAGESIZE);
length = (size_t)((filemap - ((unsigned int)filemap & ~PAGEMASK)) + length - PAGESIZE);
if (mprotect(start, length, PROT_NONE) != 0)
{ perror("mprotext"); exit(1); }
/* Close the file descriptor */
if (close(filefd) != 0) { perror("close"); exit(1); }
/* munmap the areas */
if (munmap(filemap, length) != 0 ) { perror("munmap"); exit(1); }
if (munmap(filemap2, PAGESIZE) != 0 ) { perror("munmap2"); exit(1); }
}
return 0;
}
---
The reward goes to the person who make this run the fasteest, as judged
by me :)
c.
^ permalink raw reply [flat|nested] 2+ messages in thread* [parisc-linux] [Kernel Hacker Challenge #1] loop.c source update.
2004-01-08 5:42 [parisc-linux] [Kernel Hacker Challenge #1] Make my loop.c run faster, fly higher, and win big! Carlos O'Donell
@ 2004-01-09 13:56 ` Carlos O'Donell
0 siblings, 0 replies; 2+ messages in thread
From: Carlos O'Donell @ 2004-01-09 13:56 UTC (permalink / raw)
To: parisc-linux
On Thu, Jan 08, 2004 at 12:42:12AM -0500, Carlos O'Donell wrote:
>
> pa,
>
Mistake in the code, changed up thanks to Stan who noticed I missed
setting the "start" value for the second mmap call. I was also smoking
crack when I wrote PAGEMASK down, that's what I get for issuing
challenges in the early morning.
http://www.baldric.uwo.ca/~carlos/loop.c (For those with wget fetishes).
The *NO* in the syscall comment means that I did not include that
syscall in the loop. I deemed it not important. If you think otherwise
please test and return the results.
---
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#define BUFLEN 512
#define PAGESIZE 4096
/* 4096 - 1, usefull for ~PAGEMASK */
#define PAGEMASK 0x0fff
/*
Sample trace of what glibc does...
968 open("./tst-tlsmod13.so", O_RDONLY) = 3
969 read(3, "\177ELF\1\2\1\3\0\0\0\0\0\0\0\0\0\3\0\17\0\0\0\1\0\0\10"..., 512) = 512
970 fstat64(3, {st_mode=0, st_size=4294967297000, ...}) = 0
*NO*971 getcwd("/home/carlos/src/glibc-work/tests/tst-tls13", 128) = 44
972 mmap(NULL, 69232, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x401b2000
973 mprotect(0x401b3000, 65136, PROT_NONE) = 0
974 mmap(0x401c2000, 4096, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0x401c2000
975 close(3) = 0
*NO*976 munmap(0x401a1000, 69352) = 0
977 munmap(0x401b2000, 69232) = 0
Compile this code with:
gcc -o loop loop.c
Create the test file with:
dd if=/dev/zero of=./testdata bs=1024 count=70
*/
int
main (void)
{
int i;
char buffer[BUFLEN];
void * start = NULL;
int offset = 0;
void * end = NULL;
size_t length = 0;
int filefd;
void * filemap;
void * filemap2;
struct stat statbuf;
for (i = 0; i < 1000;)
{
printf ("round %d\n",++i);
/* File is 70 * 1024 bytes */
filefd = open("./testdata", O_RDONLY);
if (filefd == -1) { perror("open"); exit(1); }
/* Read 512 bytes into a buffer... or less */
length = read(filefd, buffer, BUFLEN);
if (length == 0) { perror("read"); exit(1); }
/* Find the real size */
if (fstat(filefd, &statbuf) != 0) { perror("fstat"); exit(1); }
length = statbuf.st_size;
/* mmap without protection */
filemap = mmap (start, length, PROT_READ|PROT_EXEC, MAP_PRIVATE, filefd, offset);
if (filemap == MAP_FAILED) { perror("mmap"); exit (1); }
/* Load in a page of zeros, starting at the next page */
start = (void *)((unsigned int)(filemap + length + PAGESIZE) & ~PAGEMASK);
filemap2 = mmap (start, PAGESIZE, PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_PRIVATE|MAP_FIXED, filefd, offset);
if ( filemap2 == MAP_FAILED ) { perror("mmap2"); exit(1); }
/* Protect everything but the first page */
start = (void *)(((unsigned int)(filemap) & ~PAGEMASK) + PAGESIZE);
length = (size_t)((filemap - ((unsigned int)filemap & ~PAGEMASK)) + length - PAGESIZE);
if (mprotect(start, length, PROT_NONE) != 0)
{ perror("mprotext"); exit(1); }
/* Close the file descriptor */
if (close(filefd) != 0) { perror("close"); exit(1); }
/* munmap the areas */
if (munmap(filemap, length) != 0 ) { perror("munmap"); exit(1); }
if (munmap(filemap2, PAGESIZE) != 0 ) { perror("munmap2"); exit(1); }
}
return 0;
}
---
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2004-01-08 5:42 [parisc-linux] [Kernel Hacker Challenge #1] Make my loop.c run faster, fly higher, and win big! Carlos O'Donell
2004-01-09 13:56 ` [parisc-linux] [Kernel Hacker Challenge #1] loop.c source update Carlos O'Donell
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