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/* Low-level statistical profiling support function. Mach/Hurd version.
Copyright (C) 1995, 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <hurd.h>
#include <mach/mach4.h>
#include <mach/pc_sample.h>
#include <cthreads.h>
#include <assert.h>
#define MAX_PC_SAMPLES 512 /* XXX ought to be exported in kernel hdr */
static thread_t profile_thread = MACH_PORT_NULL;
static u_short *samples;
static size_t maxsamples;
static size_t pc_offset;
static size_t sample_scale;
static sampled_pc_seqno_t seqno;
static struct mutex lock = MUTEX_INITIALIZER;
static mach_msg_timeout_t collector_timeout; /* ms between collections. */
/* Enable statistical profiling, writing samples of the PC into at most
SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
is enabled, the system examines the user PC and increments
SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536]. If SCALE is zero,
disable profiling. Returns zero on success, -1 on error. */
static error_t
update_waiter (u_short *sample_buffer, size_t size, size_t offset, u_int scale)
{
error_t err;
if (profile_thread == MACH_PORT_NULL)
{
/* Set up the profiling collector thread. */
static void profile_waiter (void);
err = __thread_create (__mach_task_self (), &profile_thread);
if (! err)
err = __mach_setup_thread (__mach_task_self (), profile_thread,
&profile_waiter, NULL, NULL);
}
else
err = 0;
if (! err)
{
int tick; /* Microseconds per sample. */
err = __task_enable_pc_sampling (__mach_task_self (), &tick,
SAMPLED_PC_PERIODIC);
if (!err && sample_scale == 0)
/* Profiling was not turned on, so the collector thread was
suspended. Resume it. */
err = __thread_resume (profile_thread);
if (! err)
{
samples = sample_buffer;
maxsamples = size / sizeof *sample_buffer;
pc_offset = offset;
sample_scale = scale;
/* Calculate a good period for the collector thread. From TICK
and the kernel buffer size we get the length of time it takes
to fill the buffer; translate that to milliseconds for
mach_msg, and chop it in half for general lag factor. */
collector_timeout = MAX_PC_SAMPLES * tick / 1000 / 2;
}
}
return err;
}
int
profil (u_short *sample_buffer, size_t size, size_t offset, u_int scale)
{
error_t err;
__mutex_lock (&lock);
if (scale == 0)
{
/* Disable profiling. */
int count;
__thread_suspend (profile_thread);
err = __task_disable_pc_sampling (__mach_task_self (), &count);
sample_scale = 0;
seqno = 0;
}
else
err = update_waiter (sample_buffer, size, offset, scale);
__mutex_unlock (&lock);
return err ? __hurd_fail (err) : 0;
}
static void
profile_waiter (void)
{
sampled_pc_t pc_samples[MAX_PC_SAMPLES];
mach_msg_type_number_t nsamples, i;
mach_port_t rcv = __mach_reply_port ();
mach_msg_header_t msg;
error_t err;
while (1)
{
__mutex_lock (&lock);
nsamples = sizeof pc_samples / sizeof pc_samples[0];
err = __task_get_sampled_pcs (__mach_task_self (), &seqno,
pc_samples, &nsamples);
assert_perror (err);
for (i = 0; i < nsamples; ++i)
{
size_t idx = (((pc_samples[i].pc - pc_offset) / 2) *
sample_scale / 65536);
if (idx < maxsamples)
++samples[idx];
}
__vm_deallocate (__mach_task_self (),
(vm_address_t) pc_samples,
nsamples * sizeof *pc_samples);
__mutex_unlock (&lock);
__mach_msg (&msg, MACH_RCV_MSG|MACH_RCV_TIMEOUT, 0, sizeof msg,
rcv, collector_timeout, MACH_PORT_NULL);
}
}
data_set_element (_hurd_fork_locks, lock);
static void
fork_profil (void)
{
u_short *sb;
size_t n, o, ss;
error_t err;
if (profile_thread != MACH_PORT_NULL)
{
__mach_port_deallocate (__mach_task_self (), profile_thread);
profile_thread = MACH_PORT_NULL;
}
sb = samples;
samples = NULL;
n = maxsamples;
maxsamples = 0;
o = pc_offset;
pc_offset = 0;
ss = sample_scale;
sample_scale = 0;
if (ss != 0)
{
err = update_waiter (sb, n * sizeof *sb, o, ss);
assert_perror (err);
}
}
text_set_element (_hurd_fork_child_hook, fork_profil);
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