hackbench is to test Linux scheduler. The original program is at
http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c
Based on this multi-process version, a nice person created a multi-thread
version. Pls. see
http://www.bullopensource.org/posix/pi-futex/hackbench_pth.c
When I integrated them into my automation testing system, I found
a couple of issues and did some improvements.
1) Merge hackbench: I integrated hackbench_pth.c into hackbench and added a
new parameter which can be used to choose process mode or thread mode. The
default mode is process.
2) It runs too fast and ends in a couple of seconds. Sometimes it's too hard to debug
the issues. On my ia64 Montecito machines, the result looks weird when comparing
process mode and thread mode.
I want a stable result and hope the testing could run for a stable longer time, so I
might use performance tools to debug issues.
I added another new parameter,`loops`, which can be used to change variable loops,
so more messages will be passed from writers to receivers. Parameter 'loops' is equal to
100 by default.
For example on my 8-core x86_64:
[ymzhang@lkp-st01-x8664 hackbench]$ uname -a
Linux lkp-st01-x8664 2.6.24-rc6 #1 SMP Fri Dec 21 08:32:31 CST 2007 x86_64 x86_64 x86_64 GNU/Linux
[ymzhang@lkp-st01-x8664 hackbench]$ ./hackbench
Usage: hackbench [-pipe] <num groups> [process|thread] [loops]
[ymzhang@lkp-st01-x8664 hackbench]$ ./hackbench 150 process 1000
Time: 151.533
[ymzhang@lkp-st01-x8664 hackbench]$ ./hackbench 150 thread 1000
Time: 153.666
With the same new parameters, I did captured the SLUB issue discussed on LKML recently.
3) hackbench_pth.c will fail on ia64 machine because pthread_attr_setstacksize always
fails if the stack size is less than 196*1024. I moved this statement within a __ia64__ check.
This new program could be compiled with command line:
#gcc -g -Wall -o hackbench hackbench.c -lpthread
Thank Ingo for his great comments!
-yanmin
---
/* Test groups of 20 processes spraying to 20 receivers */
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/poll.h>
#define DATASIZE 100
static unsigned int loops = 100;
/*
* 0 means thread mode and others mean process (default)
*/
static unsigned int process_mode = 1;
static int use_pipes = 0;
struct sender_context {
unsigned int num_fds;
int ready_out;
int wakefd;
int out_fds[0];
};
struct receiver_context {
unsigned int num_packets;
int in_fds[2];
int ready_out;
int wakefd;
};
static void barf(const char *msg)
{
fprintf(stderr, "%s (error: %s)\n", msg, strerror(errno));
exit(1);
}
static void print_usage_exit()
{
printf("Usage: hackbench [-pipe] <num groups> [process|thread] [loops]\n");
exit(1);
}
static void fdpair(int fds[2])
{
if (use_pipes) {
if (pipe(fds) == 0)
return;
} else {
if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) == 0)
return;
}
barf("Creating fdpair");
}
/* Block until we're ready to go */
static void ready(int ready_out, int wakefd)
{
char dummy;
struct pollfd pollfd = { .fd = wakefd, .events = POLLIN };
/* Tell them we're ready. */
if (write(ready_out, &dummy, 1) != 1)
barf("CLIENT: ready write");
/* Wait for "GO" signal */
if (poll(&pollfd, 1, -1) != 1)
barf("poll");
}
/* Sender sprays loops messages down each file descriptor */
static void *sender(struct sender_context *ctx)
{
char data[DATASIZE];
unsigned int i, j;
ready(ctx->ready_out, ctx->wakefd);
/* Now pump to every receiver. */
for (i = 0; i < loops; i++) {
for (j = 0; j < ctx->num_fds; j++) {
int ret, done = 0;
again:
ret = write(ctx->out_fds[j], data + done, sizeof(data)-done);
if (ret < 0)
barf("SENDER: write");
done += ret;
if (done < sizeof(data))
goto again;
}
}
return NULL;
}
/* One receiver per fd */
static void *receiver(struct receiver_context* ctx)
{
unsigned int i;
if (process_mode)
close(ctx->in_fds[1]);
/* Wait for start... */
ready(ctx->ready_out, ctx->wakefd);
/* Receive them all */
for (i = 0; i < ctx->num_packets; i++) {
char data[DATASIZE];
int ret, done = 0;
again:
ret = read(ctx->in_fds[0], data + done, DATASIZE - done);
if (ret < 0)
barf("SERVER: read");
done += ret;
if (done < DATASIZE)
goto again;
}
return NULL;
}
pthread_t create_worker(void *ctx, void *(*func)(void *))
{
pthread_attr_t attr;
pthread_t childid;
int err;
if (process_mode) {
/* process mode */
/* Fork the receiver. */
switch (fork()) {
case -1: barf("fork()");
case 0:
(*func) (ctx);
exit(0);
}
return (pthread_t) 0;
}
if (pthread_attr_init(&attr) != 0)
barf("pthread_attr_init:");
#ifndef __ia64__
if (pthread_attr_setstacksize(&attr, (size_t)(16*1024)) != 0)
barf("pthread_attr_setstacksize");
#endif
if ((err=pthread_create(&childid, &attr, func, ctx)) != 0) {
fprintf(stderr, "pthread_create failed: %s (%d)\n", strerror(err), err);
exit(-1);
}
return (childid);
}
void reap_worker(pthread_t id)
{
int status;
if (process_mode) {
/* process mode */
wait(&status);
if (!WIFEXITED(status))
exit(1);
} else
pthread_join(id, (void**)&status);
}
/* One group of senders and receivers */
static unsigned int group(pthread_t *pth,
unsigned int num_fds,
int ready_out,
int wakefd)
{
unsigned int i;
struct sender_context* snd_ctx = malloc (sizeof(struct sender_context)
+num_fds*sizeof(int));
for (i = 0; i < num_fds; i++) {
int fds[2];
struct receiver_context* ctx = malloc (sizeof(*ctx));
if (!ctx)
barf("malloc()");
/* Create the pipe between client and server */
fdpair(fds);
ctx->num_packets = num_fds*loops;
ctx->in_fds[0] = fds[0];
ctx->in_fds[1] = fds[1];
ctx->ready_out = ready_out;
ctx->wakefd = wakefd;
pth[i] = create_worker(ctx, (void *)(void *)receiver);
snd_ctx->out_fds[i] = fds[1];
if (process_mode)
close(fds[0]);
}
/* Now we have all the fds, fork the senders */
for (i = 0; i < num_fds; i++) {
snd_ctx->ready_out = ready_out;
snd_ctx->wakefd = wakefd;
snd_ctx->num_fds = num_fds;
pth[num_fds+i] = create_worker(snd_ctx, (void *)(void *)sender);
}
/* Close the fds we have left */
if (process_mode)
for (i = 0; i < num_fds; i++)
close(snd_ctx->out_fds[i]);
/* Return number of children to reap */
return num_fds * 2;
}
int main(int argc, char *argv[])
{
unsigned int i, num_groups, total_children;
struct timeval start, stop, diff;
unsigned int num_fds = 20;
int readyfds[2], wakefds[2];
char dummy;
pthread_t *pth_tab;
if (argv[1] && strcmp(argv[1], "-pipe") == 0) {
use_pipes = 1;
argc--;
argv++;
}
if (argc < 2 || (num_groups = atoi(argv[1])) == 0)
print_usage_exit();
if (argc > 2) {
if ( !strcmp(argv[2], "process") )
process_mode = 1;
else if ( !strcmp(argv[2], "thread") )
process_mode = 0;
else
print_usage_exit();
}
if (argc > 3)
loops = atoi(argv[3]);
pth_tab = malloc(num_fds * 2 * num_groups * sizeof(pthread_t));
if (!pth_tab)
barf("main:malloc()");
fdpair(readyfds);
fdpair(wakefds);
total_children = 0;
for (i = 0; i < num_groups; i++)
total_children += group(pth_tab+total_children, num_fds, readyfds[1], wakefds[0]);
/* Wait for everyone to be ready */
for (i = 0; i < total_children; i++)
if (read(readyfds[0], &dummy, 1) != 1)
barf("Reading for readyfds");
gettimeofday(&start, NULL);
/* Kick them off */
if (write(wakefds[1], &dummy, 1) != 1)
barf("Writing to start them");
/* Reap them all */
for (i = 0; i < total_children; i++)
reap_worker(pth_tab[i]);
gettimeofday(&stop, NULL);
/* Print time... */
timersub(&stop, &start, &diff);
printf("Time: %lu.%03lu\n", diff.tv_sec, diff.tv_usec/1000);
exit(0);
}
* Zhang, Yanmin <[email protected]> wrote:
> hackbench is to test Linux scheduler. The original program is at
> http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c
> Based on this multi-process version, a nice person created a
> multi-thread version. Pls. see
> http://www.bullopensource.org/posix/pi-futex/hackbench_pth.c
great. I've uploaded your unified & improved version to:
http://redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
(i made some small changes - two warning fixes on gcc 4.2 and a default
of 10 groups when hackbench is called without parameters, plus a
printout.)
Ingo
Ingo Molnar wrote:
> * Zhang, Yanmin <[email protected]> wrote:
>
>
>> hackbench is to test Linux scheduler. The original program is at
>> http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c
>> Based on this multi-process version, a nice person created a
>> multi-thread version. Pls. see
>> http://www.bullopensource.org/posix/pi-futex/hackbench_pth.c
>>
>
> great. I've uploaded your unified & improved version to:
>
> http://redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
>
> (i made some small changes - two warning fixes on gcc 4.2 and a default
> of 10 groups when hackbench is called without parameters, plus a
> printout.)
>
On x86-64 there's a bug [*], that causes hackbench to segfault when
compiled with optimizations:
in reap_worker():
int status;
...
pthread_join(id, (void **)(void *)&status);
That is not correct, sizeof(void*) > sizeof(int) on x86-64.
Something gets overwritten on the stack, I tried with gcc
-fstack-protector, but it doesn't detect it !?
After applying the patch, it no longer segfaults.
This patch fixes it:
--- hackbench.c 2008-01-04 10:08:26.000000000 +0200
+++ ../hackbench.c 2008-01-04 13:45:22.000000000 +0200
@@ -241,8 +241,10 @@
wait(&status);
if (!WIFEXITED(status))
exit(1);
- } else
- pthread_join(id, (void **)(void *)&status);
+ } else {
+ void* status;
+ pthread_join(id, (void **)&status);
+ }
}
/* One group of senders and receivers */
----------------
I also notice that the thread version is slower, than process version:
$ ./hackbench 5 thread
Running with 5*40 (== 200) tasks.
Time: 0.413
$ ./hackbench 5 thread
Running with 5*40 (== 200) tasks.
Time: 0.423
$ ./hackbench 5 thread 20
Running with 5*40 (== 200) tasks.
Time: 0.093
$ ./hackbench 5 thread 200
Running with 5*40 (== 200) tasks.
Time: 0.827
$ ./hackbench 5 thread 2000
Running with 5*40 (== 200) tasks.
Time: 8.409
$ ./hackbench 5 process 2000
Running with 5*40 (== 200) tasks.
Time: 7.669
$ ./hackbench -pipe 5 process 2000
Running with 5*40 (== 200) tasks.
Time: 3.416
$ ./hackbench -pipe 5 thread 2000
Running with 5*40 (== 200) tasks.
Time: 4.320
[*]
$ uname -a
Linux lightspeed2 2.6.24-rc6-ge697789d #3 Wed Jan 2 11:15:05 EET 2008
x86_64 GNU/Linux
$ gcc -v
Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v
--enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr
--enable-shared --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --enable-nls
--with-gxx-include-dir=/usr/include/c++/4.2 --program-suffix=-4.2
--enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr
--enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.2.3 20071123 (prerelease) (Debian 4.2.2-4)
$ wget http://redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
--13:40:53-- http://redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
=> `hackbench.c'
Resolving redhat.com... 209.132.177.50
Connecting to redhat.com|209.132.177.50|:80... connected.
HTTP request sent, awaiting response... 302 Found
Location: http://www.redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
[following]
--13:40:54-- http://www.redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
=> `hackbench.c'
Resolving http://www.redhat.com... 209.132.177.50
Connecting to http://www.redhat.com|209.132.177.50|:80... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: http://people.redhat.com/mingo/cfs-scheduler/tools/hackbench.c
[following]
--13:40:54-- http://people.redhat.com/mingo/cfs-scheduler/tools/hackbench.c
=> `hackbench.c'
Resolving people.redhat.com... 66.187.233.237
Connecting to people.redhat.com|66.187.233.237|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 8,455 (8.3K) [text/plain]
100%[====================================================================================================================>]
8,455 --.--K/s
13:40:55 (61.93 KB/s) - `hackbench.c' saved [8455/8455]
$ gcc -O2 -g -Wall -o hackbench hackbench.c -lpthread
hackbench.c:32:66: warning: missing terminating ' character
$ ./hackbench 1 thread
Running with 1*40 (== 40) tasks.
Segmentation fault
$ valgrind --trace-children=yes ./hackbench 1 thread
==27332== Memcheck, a memory error detector.
==27332== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
==27332== Using LibVEX rev 1804, a library for dynamic binary translation.
==27332== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
==27332== Using valgrind-3.3.0-Debian, a dynamic binary instrumentation
framework.
==27332== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
==27332== For more details, rerun with: -v
==27332==
Running with 1*40 (== 40) tasks.
==27332== Thread 2:
==27332== Syscall param write(buf) points to uninitialised byte(s)
==27332== at 0x4C1854B: (within /usr/lib/debug/libpthread-2.7.so)
==27332== by 0x400C34: ready (hackbench.c:138)
==27332== by 0x400C97: receiver (hackbench.c:182)
==27332== by 0x4C113F6: start_thread (pthread_create.c:297)
==27332== by 0x4EFD91C: clone (in /usr/lib/debug/libc-2.7.so)
==27332== Address 0x558a09f is on thread 2's stack
==27332==
==27332== Thread 22:
==27332== Syscall param write(buf) points to uninitialised byte(s)
==27332== at 0x4C1854B: (within /usr/lib/debug/libpthread-2.7.so)
==27332== by 0x400C34: ready (hackbench.c:138)
==27332== by 0x400D33: sender (hackbench.c:152)
==27332== by 0x4C113F6: start_thread (pthread_create.c:297)
==27332== by 0x4EFD91C: clone (in /usr/lib/debug/libc-2.7.so)
==27332== Address 0x55da07f is on thread 22's stack
==27332==
==27332== Thread 40:
==27332== Syscall param write(buf) points to uninitialised byte(s)
==27332== at 0x4C1854B: (within /usr/lib/debug/libpthread-2.7.so)
==27332== by 0x400D6E: sender (hackbench.c:160)
==27332== by 0x4C113F6: start_thread (pthread_create.c:297)
==27332== by 0x4EFD91C: clone (in /usr/lib/debug/libc-2.7.so)
==27332== Address 0x56220a0 is on thread 40's stack
==27332==
==27332== Thread 1:
==27332== Jump to the invalid address stated on the next line
==27332== at 0x0: ???
==27332== by 0x518702F: ???
==27332== by 0xFFFFFFFF: ???
==27332== by 0x518702F: ???
==27332== by 0x2800000000: ???
==27332== Address 0x0 is not stack'd, malloc'd or (recently) free'd
==27332==
==27332== Process terminating with default action of signal 11 (SIGSEGV)
==27332== Bad permissions for mapped region at address 0x0
==27332== at 0x0: ???
==27332== by 0x518702F: ???
==27332== by 0xFFFFFFFF: ???
==27332== by 0x518702F: ???
==27332== by 0x2800000000: ???
==27332==
==27332== ERROR SUMMARY: 40041 errors from 4 contexts (suppressed: 8 from 1)
==27332== malloc/free: in use at exit: 11,420 bytes in 61 blocks.
==27332== malloc/free: 62 allocs, 1 frees, 11,692 bytes allocated.
==27332== For counts of detected errors, rerun with: -v
==27332== searching for pointers to 61 not-freed blocks.
==27332== checked 560,688 bytes.
==27332==
==27332== LEAK SUMMARY:
==27332== definitely lost: 20 bytes in 1 blocks.
==27332== possibly lost: 10,608 bytes in 39 blocks.
==27332== still reachable: 792 bytes in 21 blocks.
==27332== suppressed: 0 bytes in 0 blocks.
==27332== Rerun with --leak-check=full to see details of leaked memory.
Segmentation fault
Best regards,
--Edwin
On Jan 4, 2008 3:10 AM, Ingo Molnar <[email protected]> wrote:
> http://redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
>
Why not lose the #ifdef and just use PTHREAD_STACK_MIN?
Lee
* T?r?k Edwin <[email protected]> wrote:
> On x86-64 there's a bug [*], that causes hackbench to segfault when
> compiled with optimizations:
> in reap_worker():
> int status;
> ...
> pthread_join(id, (void **)(void *)&status);
>
> That is not correct, sizeof(void*) > sizeof(int) on x86-64.
> Something gets overwritten on the stack, I tried with gcc
> -fstack-protector, but it doesn't detect it !?
> After applying the patch, it no longer segfaults.
>
> This patch fixes it:
> --- hackbench.c 2008-01-04 10:08:26.000000000 +0200
> +++ ../hackbench.c 2008-01-04 13:45:22.000000000 +0200
> @@ -241,8 +241,10 @@
> wait(&status);
> if (!WIFEXITED(status))
> exit(1);
> - } else
> - pthread_join(id, (void **)(void *)&status);
> + } else {
> + void* status;
> + pthread_join(id, (void **)&status);
> + }
> }
thanks, applied & updated the file.
Ingo
On Fri, 2008-01-04 at 13:51 +0200, T?r?k Edwin wrote:
> Ingo Molnar wrote:
> > * Zhang, Yanmin <[email protected]> wrote:
> >
> >
> >> hackbench is to test Linux scheduler. The original program is at
> >> http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c
> >> Based on this multi-process version, a nice person created a
> >> multi-thread version. Pls. see
> >> http://www.bullopensource.org/posix/pi-futex/hackbench_pth.c
> >>
> >
> > great. I've uploaded your unified & improved version to:
> >
> > http://redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
> >
> > (i made some small changes - two warning fixes on gcc 4.2 and a default
> > of 10 groups when hackbench is called without parameters, plus a
> > printout.)
> >
>
> On x86-64 there's a bug [*], that causes hackbench to segfault when
> compiled with optimizations:
> in reap_worker():
> int status;
> ...
> pthread_join(id, (void **)(void *)&status);
>
> That is not correct, sizeof(void*) > sizeof(int) on x86-64.
> Something gets overwritten on the stack, I tried with gcc
> -fstack-protector, but it doesn't detect it !?
> After applying the patch, it no longer segfaults.
>
> This patch fixes it:
Thanks.
> --- hackbench.c 2008-01-04 10:08:26.000000000 +0200
> +++ ../hackbench.c 2008-01-04 13:45:22.000000000 +0200
> @@ -241,8 +241,10 @@
> wait(&status);
> if (!WIFEXITED(status))
> exit(1);
> - } else
> - pthread_join(id, (void **)(void *)&status);
> + } else {
> + void* status;
> + pthread_join(id, (void **)&status);
We could use NULL to replace &status.
> + }
> }
>
> /* One group of senders and receivers */
>
> ----------------
>
>
> I also notice that the thread version is slower, than process version:
I also noticed that. I did an initial check and found the root cause might
be the difference between pthread_join and wait. wait will wait any sub-process
to exit and pthread_join just waits a specific thread to exit. If the first thread
exits lastly, it will take the main thread a longer time to reap sub-threads in the end.
>
> $ ./hackbench 5 thread
> Running with 5*40 (== 200) tasks.
> Time: 0.413
> $ ./hackbench 5 thread
> Running with 5*40 (== 200) tasks.
> Time: 0.423
> $ ./hackbench 5 thread 20
> Running with 5*40 (== 200) tasks.
> Time: 0.093
> $ ./hackbench 5 thread 200
> Running with 5*40 (== 200) tasks.
> Time: 0.827
> $ ./hackbench 5 thread 2000
> Running with 5*40 (== 200) tasks.
> Time: 8.409
> $ ./hackbench 5 process 2000
> Running with 5*40 (== 200) tasks.
> Time: 7.669
> $ ./hackbench -pipe 5 process 2000
> Running with 5*40 (== 200) tasks.
> Time: 3.416
> $ ./hackbench -pipe 5 thread 2000
> Running with 5*40 (== 200) tasks.
> Time: 4.320
>
> [*]
> $ uname -a
> Linux lightspeed2 2.6.24-rc6-ge697789d #3 Wed Jan 2 11:15:05 EET 2008
> x86_64 GNU/Linux
> $ gcc -v
> Using built-in specs.
> Target: x86_64-linux-gnu
> Configured with: ../src/configure -v
> --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr
> --enable-shared --with-system-zlib --libexecdir=/usr/lib
> --without-included-gettext --enable-threads=posix --enable-nls
> --with-gxx-include-dir=/usr/include/c++/4.2 --program-suffix=-4.2
> --enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr
> --enable-checking=release --build=x86_64-linux-gnu
> --host=x86_64-linux-gnu --target=x86_64-linux-gnu
> Thread model: posix
> gcc version 4.2.3 20071123 (prerelease) (Debian 4.2.2-4)
> $ wget http://redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
> --13:40:53-- http://redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
> => `hackbench.c'
> Resolving redhat.com... 209.132.177.50
> Connecting to redhat.com|209.132.177.50|:80... connected.
> HTTP request sent, awaiting response... 302 Found
> Location: http://www.redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
> [following]
> --13:40:54-- http://www.redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
> => `hackbench.c'
> Resolving http://www.redhat.com... 209.132.177.50
> Connecting to http://www.redhat.com|209.132.177.50|:80... connected.
> HTTP request sent, awaiting response... 301 Moved Permanently
> Location: http://people.redhat.com/mingo/cfs-scheduler/tools/hackbench.c
> [following]
> --13:40:54-- http://people.redhat.com/mingo/cfs-scheduler/tools/hackbench.c
> => `hackbench.c'
> Resolving people.redhat.com... 66.187.233.237
> Connecting to people.redhat.com|66.187.233.237|:80... connected.
> HTTP request sent, awaiting response... 200 OK
> Length: 8,455 (8.3K) [text/plain]
>
> 100%[====================================================================================================================>]
> 8,455 --.--K/s
>
> 13:40:55 (61.93 KB/s) - `hackbench.c' saved [8455/8455]
>
> $ gcc -O2 -g -Wall -o hackbench hackbench.c -lpthread
> hackbench.c:32:66: warning: missing terminating ' character
> $ ./hackbench 1 thread
> Running with 1*40 (== 40) tasks.
> Segmentation fault
>
> $ valgrind --trace-children=yes ./hackbench 1 thread
> ==27332== Memcheck, a memory error detector.
> ==27332== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
> ==27332== Using LibVEX rev 1804, a library for dynamic binary translation.
> ==27332== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
> ==27332== Using valgrind-3.3.0-Debian, a dynamic binary instrumentation
> framework.
> ==27332== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
> ==27332== For more details, rerun with: -v
> ==27332==
> Running with 1*40 (== 40) tasks.
> ==27332== Thread 2:
> ==27332== Syscall param write(buf) points to uninitialised byte(s)
> ==27332== at 0x4C1854B: (within /usr/lib/debug/libpthread-2.7.so)
> ==27332== by 0x400C34: ready (hackbench.c:138)
> ==27332== by 0x400C97: receiver (hackbench.c:182)
> ==27332== by 0x4C113F6: start_thread (pthread_create.c:297)
> ==27332== by 0x4EFD91C: clone (in /usr/lib/debug/libc-2.7.so)
> ==27332== Address 0x558a09f is on thread 2's stack
> ==27332==
> ==27332== Thread 22:
> ==27332== Syscall param write(buf) points to uninitialised byte(s)
> ==27332== at 0x4C1854B: (within /usr/lib/debug/libpthread-2.7.so)
> ==27332== by 0x400C34: ready (hackbench.c:138)
> ==27332== by 0x400D33: sender (hackbench.c:152)
> ==27332== by 0x4C113F6: start_thread (pthread_create.c:297)
> ==27332== by 0x4EFD91C: clone (in /usr/lib/debug/libc-2.7.so)
> ==27332== Address 0x55da07f is on thread 22's stack
> ==27332==
> ==27332== Thread 40:
> ==27332== Syscall param write(buf) points to uninitialised byte(s)
> ==27332== at 0x4C1854B: (within /usr/lib/debug/libpthread-2.7.so)
> ==27332== by 0x400D6E: sender (hackbench.c:160)
> ==27332== by 0x4C113F6: start_thread (pthread_create.c:297)
> ==27332== by 0x4EFD91C: clone (in /usr/lib/debug/libc-2.7.so)
> ==27332== Address 0x56220a0 is on thread 40's stack
> ==27332==
> ==27332== Thread 1:
> ==27332== Jump to the invalid address stated on the next line
> ==27332== at 0x0: ???
> ==27332== by 0x518702F: ???
> ==27332== by 0xFFFFFFFF: ???
> ==27332== by 0x518702F: ???
> ==27332== by 0x2800000000: ???
> ==27332== Address 0x0 is not stack'd, malloc'd or (recently) free'd
> ==27332==
> ==27332== Process terminating with default action of signal 11 (SIGSEGV)
> ==27332== Bad permissions for mapped region at address 0x0
> ==27332== at 0x0: ???
> ==27332== by 0x518702F: ???
> ==27332== by 0xFFFFFFFF: ???
> ==27332== by 0x518702F: ???
> ==27332== by 0x2800000000: ???
> ==27332==
> ==27332== ERROR SUMMARY: 40041 errors from 4 contexts (suppressed: 8 from 1)
> ==27332== malloc/free: in use at exit: 11,420 bytes in 61 blocks.
> ==27332== malloc/free: 62 allocs, 1 frees, 11,692 bytes allocated.
> ==27332== For counts of detected errors, rerun with: -v
> ==27332== searching for pointers to 61 not-freed blocks.
> ==27332== checked 560,688 bytes.
> ==27332==
> ==27332== LEAK SUMMARY:
> ==27332== definitely lost: 20 bytes in 1 blocks.
> ==27332== possibly lost: 10,608 bytes in 39 blocks.
> ==27332== still reachable: 792 bytes in 21 blocks.
> ==27332== suppressed: 0 bytes in 0 blocks.
> ==27332== Rerun with --leak-check=full to see details of leaked memory.
> Segmentation fault
>
>
>
> Best regards,
> --Edwin
On Fri, 2008-01-04 at 07:44 -0500, Lee Revell wrote:
> On Jan 4, 2008 3:10 AM, Ingo Molnar <[email protected]> wrote:
> > http://redhat.com/~mingo/cfs-scheduler/tools/hackbench.c
> >
>
> Why not lose the #ifdef and just use PTHREAD_STACK_MIN?
That's a good idea.
Thanks,
-yanmin
---
--- hackbench.c.orig 2008-01-10 08:24:36.000000000 +0800
+++ hackbench.c 2008-01-10 08:25:12.000000000 +0800
@@ -151,10 +151,8 @@ pthread_t create_worker(void *ctx, void
if (pthread_attr_init(&attr) != 0)
barf("pthread_attr_init:");
-#ifndef __ia64__
- if (pthread_attr_setstacksize(&attr, (size_t)(16*1024)) != 0)
+ if (pthread_attr_setstacksize(&attr, PTHREAD_STACK_MIN) != 0)
barf("pthread_attr_setstacksize");
-#endif
if ((err=pthread_create(&childid, &attr, func, ctx)) != 0) {
fprintf(stderr, "pthread_create failed: %s (%d)\n", strerror(err), err);