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authorUlrich Drepper <drepper@redhat.com>1997-08-08 00:36:47 +0000
committerUlrich Drepper <drepper@redhat.com>1997-08-08 00:36:47 +0000
commita3412bbd3d319f26507f1ea968bda97df7d21c0c (patch)
tree5dae4ad9b9e414d84ec2019ceb9a5bee9dd7cd4e
parent21b29282a26415a96e2f84c38c48d5c215ce1bb8 (diff)
(profile_waiter): Do vm_deallocate
after releasing lock. Use special RPC stubs and avoid assert, thus making this function entirely independent of the threadvar mechanism and of cthreads. (lock): Convert to be a spin lock instead of a mutex, so that the waiter thread need not use cthreads. Use a fork prepare hook instead of _hurd_fork_locks to make sure we are clean before forking. (fork_profil_child): Renamed from fork_profil. (profil_reply_port): New variable. (profil_vm_deallocate, profil_task_get_sampled_pcs): Special RPC stubs made by special hacks. (fetch_samples): New function, guts from profile_waiter. (profile_waiter): Use fetch_samples. (profil): When turning off profiling, fetch the last bunch of samples before disabling PC sampling. (fetch_samples): Add prototype. (fetch_samples): Sample buffer need not be vm_deallocated; it's a stack buffer. (profil_vm_deallocate): Delete prototype. (#include <../mach/RPC_vm_deallocate_rpc.c>): Drop this inclusion. (fetch_samples): Initialize NSAMPLES. (fetch_samples): Do arithmetic on PC's in long long to avoid overflow. (fetch_samples): Put parens in the right place.
-rw-r--r--sysdeps/mach/hurd/profil.c181
1 files changed, 138 insertions, 43 deletions
diff --git a/sysdeps/mach/hurd/profil.c b/sysdeps/mach/hurd/profil.c
index 41c7c4b956..d76cc25a3c 100644
--- a/sysdeps/mach/hurd/profil.c
+++ b/sysdeps/mach/hurd/profil.c
@@ -1,21 +1,21 @@
/* 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.
+ Copyright (C) 1995, 1996, 1997 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 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.
+ 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. */
+ 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., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
#include <sys/types.h>
#include <unistd.h>
@@ -34,10 +34,20 @@ 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 spin_lock_t lock = SPIN_LOCK_INITIALIZER;
static mach_msg_timeout_t collector_timeout; /* ms between collections. */
static int profile_tick;
+/* Reply port used by profiler thread */
+static mach_port_t profil_reply_port;
+
+/* Forwards */
+static kern_return_t profil_task_get_sampled_pcs (mach_port_t,
+ sampled_pc_seqno_t *,
+ sampled_pc_array_t,
+ mach_msg_type_number_t *);
+static void fetch_samples (void);
+
/* 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
@@ -87,7 +97,7 @@ update_waiter (u_short *sample_buffer, size_t size, size_t offset, u_int scale)
}
int
-__profile_frequency ()
+__profile_frequency (void)
{
return profile_tick;
}
@@ -97,13 +107,20 @@ profil (u_short *sample_buffer, size_t size, size_t offset, u_int scale)
{
error_t err;
- __mutex_lock (&lock);
+ __spin_lock (&lock);
if (scale == 0)
{
/* Disable profiling. */
int count;
- __thread_suspend (profile_thread);
+
+ if (profile_thread != MACH_PORT_NULL)
+ __thread_suspend (profile_thread);
+
+ /* Fetch the last set of samples */
+ if (sample_scale)
+ fetch_samples ();
+
err = __task_disable_pc_sampling (__mach_task_self (), &count);
sample_scale = 0;
seqno = 0;
@@ -111,57 +128,102 @@ profil (u_short *sample_buffer, size_t size, size_t offset, u_int scale)
else
err = update_waiter (sample_buffer, size, offset, scale);
- __mutex_unlock (&lock);
+ __spin_unlock (&lock);
return err ? __hurd_fail (err) : 0;
}
+/* Fetch PC samples. This function must be very careful not to depend
+ on Hurd threadvar variables. We arrange that by using a special
+ stub arranged for at the end of this file. */
static void
-profile_waiter (void)
+fetch_samples (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)
+ nsamples = MAX_PC_SAMPLES;
+
+ err = profil_task_get_sampled_pcs (__mach_task_self (), &seqno,
+ pc_samples, &nsamples);
+ if (err)
{
- __mutex_lock (&lock);
+ static error_t special_profil_failure;
+ static volatile int a, b, c;
- nsamples = sizeof pc_samples / sizeof pc_samples[0];
- err = __task_get_sampled_pcs (__mach_task_self (), &seqno,
- pc_samples, &nsamples);
- assert_perror (err);
+ special_profil_failure = err;
+ a = 1;
+ b = 0;
+ while (1)
+ c = a / b;
+ }
- for (i = 0; i < nsamples; ++i)
- {
- size_t idx = (((pc_samples[i].pc - pc_offset) / 2) *
- sample_scale / 65536);
- if (idx < maxsamples)
- ++samples[idx];
- }
+ for (i = 0; i < nsamples; ++i)
+ {
+ /* Do arithmetic in long long to avoid overflow problems. */
+ long long pc_difference = pc_samples[i].pc - pc_offset;
+ size_t idx = ((pc_difference / 2) * sample_scale) / 65536;
+ if (idx < maxsamples)
+ ++samples[idx];
+ }
+}
+
+
+/* This function must be very careful not to depend on Hurd threadvar
+ variables. We arrange that by using special stubs arranged for at the
+ end of this file. */
+static void
+profile_waiter (void)
+{
+ mach_msg_header_t msg;
+ mach_port_t timeout_reply_port;
+
+ profil_reply_port = __mach_reply_port ();
+ timeout_reply_port = __mach_reply_port ();
- __vm_deallocate (__mach_task_self (),
- (vm_address_t) pc_samples,
- nsamples * sizeof *pc_samples);
+ while (1)
+ {
+ __spin_lock (&lock);
+
+ fetch_samples ();
- __mutex_unlock (&lock);
+ __spin_unlock (&lock);
__mach_msg (&msg, MACH_RCV_MSG|MACH_RCV_TIMEOUT, 0, sizeof msg,
- rcv, collector_timeout, MACH_PORT_NULL);
+ timeout_reply_port, collector_timeout, MACH_PORT_NULL);
}
}
-data_set_element (_hurd_fork_locks, lock);
+/* Fork interaction */
+
+/* Before fork, lock the interlock so that we are in a clean state. */
+static void
+fork_profil_prepare (void)
+{
+ __spin_lock (&lock);
+}
+text_set_element (_hurd_fork_prepare_hook, fork_profil_prepare);
+
+/* In the parent, unlock the interlock once fork is complete. */
+static void
+fork_profil_parent (void)
+{
+ __spin_unlock (&lock);
+}
+text_set_element (_hurd_fork_parent_hook, fork_profil_parent);
+/* In the childs, unlock the interlock, and start a profiling thread up
+ if necessary. */
static void
-fork_profil (void)
+fork_profil_child (void)
{
u_short *sb;
size_t n, o, ss;
error_t err;
+ __spin_unlock (&lock);
+
if (profile_thread != MACH_PORT_NULL)
{
__mach_port_deallocate (__mach_task_self (), profile_thread);
@@ -183,4 +245,37 @@ fork_profil (void)
assert_perror (err);
}
}
-text_set_element (_hurd_fork_child_hook, fork_profil);
+text_set_element (_hurd_fork_child_hook, fork_profil_child);
+
+
+
+
+/* Special RPC stubs for profile_waiter are made by including the normal
+ source code, with special CPP state to prevent it from doing the
+ usual thing. */
+
+/* Include these first; then our #define's will take full effect, not
+ being overridden. */
+#include <mach/mig_support.h>
+
+/* This need not do anything; it is always associated with errors, which
+ are fatal in profile_waiter anyhow. */
+#define __mig_put_reply_port(foo)
+
+/* Use our static variable instead of the usual threadvar mechanism for
+ this. */
+#define __mig_get_reply_port() profil_reply_port
+
+/* Make the functions show up as static */
+#define mig_external static
+
+/* Turn off the attempt to generate ld aliasing records. */
+#undef weak_alias
+#define weak_alias(a,b)
+
+/* And change their names to avoid confusing disasters. */
+#define __vm_deallocate_rpc profil_vm_deallocate
+#define __task_get_sampled_pcs profil_task_get_sampled_pcs
+
+/* And include the source code */
+#include <../mach/RPC_task_get_sampled_pcs.c>