From: Tomas Hruby <tom@minix3.org>
Date: Thu, 23 Sep 2010 10:49:48 +0000 (+0000)
Subject: Internal 64M buffer for profiling
X-Git-Tag: v3.2.0~812
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/Bv9ARM.ch10.html?a=commitdiff_plain;h=87c576584d73f8ba208602735e43913409204ab8;p=minix.git

Internal 64M buffer for profiling

- when profiling is compiled in kernel includes a 64M buffer for
  sample

- 64M is the default used by profile tool as its buffer

- when using nmi profiling it is not possible to always copy sample
  stright to userland as the nmi may (and does) happen in bad moments

- reduces sampling overhead as samples are copied out only when
  profiling stops
---

diff --git a/kernel/profile.c b/kernel/profile.c
index 626202338..4319eccd5 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -63,32 +63,26 @@ PUBLIC void stop_profile_clock()
 
 PRIVATE sprof_save_sample(struct proc * p)
 {
-	struct sprof_sample s;
+	struct sprof_sample *s;
 
-	s.proc = p->p_endpoint;
-	s.pc = (void *) p->p_reg.pc;
+	s = (struct sprof_sample *) (sprof_sample_buffer + sprof_info.mem_used);
 
-	/* Store sample (process name and program counter). */
-	data_copy(KERNEL, (vir_bytes) &s,
-			sprof_ep, sprof_data_addr_vir + sprof_info.mem_used,
-			sizeof(s));
+	s->proc = p->p_endpoint;
+	s->pc = (void *) p->p_reg.pc;
 
-	sprof_info.mem_used += sizeof(s);
+	sprof_info.mem_used += sizeof(struct sprof_sample);
 }
 
 PRIVATE sprof_save_proc(struct proc * p)
 {
-	struct sprof_proc s;
+	struct sprof_proc * s;
 
-	s.proc = p->p_endpoint;
-	memcpy(s.name, p->p_name, P_NAME_LEN);
+	s = (struct sprof_proc *) (sprof_sample_buffer + sprof_info.mem_used);
 
-	/* Store sample (process name and program counter). */
-	data_copy(KERNEL, (vir_bytes) &s,
-			sprof_ep, sprof_data_addr_vir + sprof_info.mem_used,
-			sizeof(s));
+	s->proc = p->p_endpoint;
+	memcpy(&s->name, p->p_name, P_NAME_LEN);
 
-	sprof_info.mem_used += sizeof(s);
+	sprof_info.mem_used += sizeof(struct sprof_proc);
 }
 
 PRIVATE void profile_sample(struct proc * p)
@@ -100,7 +94,9 @@ PRIVATE void profile_sample(struct proc * p)
 	  return;
 
   /* Check if enough memory available before writing sample. */
-  if (sprof_info.mem_used + sizeof(sprof_info) > sprof_mem_size) {
+  if (sprof_info.mem_used + sizeof(sprof_info) +
+		  2*sizeof(struct sprof_sample) +
+		  2*sizeof(struct sprof_sample) > sprof_mem_size) {
 	sprof_info.mem_used = -1;
 	return;
   }
diff --git a/kernel/profile.h b/kernel/profile.h
index 275ec8711..5580bf544 100644
--- a/kernel/profile.h
+++ b/kernel/profile.h
@@ -7,6 +7,9 @@
 
 #include "arch_watchdog.h"
 
+#define SAMPLE_BUFFER_SIZE	(64 << 20)
+EXTERN char sprof_sample_buffer[SAMPLE_BUFFER_SIZE];
+
 EXTERN int sprofiling;			/* whether profiling is running */
 EXTERN int sprofiling_type;			/* whether profiling is running */
 EXTERN int sprof_mem_size;		/* available user memory for data */
diff --git a/kernel/system/do_sprofile.c b/kernel/system/do_sprofile.c
index d4f4b404d..e5aebc821 100644
--- a/kernel/system/do_sprofile.c
+++ b/kernel/system/do_sprofile.c
@@ -65,7 +65,8 @@ PUBLIC int do_sprofile(struct proc * caller, message * m_ptr)
 	sprof_info.system_samples = 0;
 	sprof_info.user_samples = 0;
 
-	sprof_mem_size = m_ptr->PROF_MEM_SIZE;
+	sprof_mem_size = m_ptr->PROF_MEM_SIZE < SAMPLE_BUFFER_SIZE ?
+				m_ptr->PROF_MEM_SIZE : SAMPLE_BUFFER_SIZE;
 
 	switch (sprofiling_type = m_ptr->PROF_INTR_TYPE) {
 		case PROF_RTC:
@@ -111,6 +112,8 @@ PUBLIC int do_sprofile(struct proc * caller, message * m_ptr)
 
 	data_copy(KERNEL, (vir_bytes) &sprof_info,
 		sprof_ep, sprof_info_addr_vir, sizeof(sprof_info));
+	data_copy(KERNEL, (vir_bytes) sprof_sample_buffer,
+		sprof_ep, sprof_data_addr_vir, sprof_info.mem_used);
 
 	clean_seen_flag();