From 8dbc50c322619eb821907e8dba75252f5378c712 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Wed, 26 Nov 2008 15:00:52 +0100 Subject: oprofile: fix typo Signed-off-by: Robert Richter --- drivers/oprofile/buffer_sync.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/oprofile/buffer_sync.c') diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c index b55cd23ffdef..774b081b9b7f 100644 --- a/drivers/oprofile/buffer_sync.c +++ b/drivers/oprofile/buffer_sync.c @@ -272,7 +272,7 @@ static void increment_tail(struct oprofile_cpu_buffer *b) { unsigned long new_tail = b->tail_pos + 1; - rmb(); /* be sure fifo pointers are synchromized */ + rmb(); /* be sure fifo pointers are synchronized */ if (new_tail < b->buffer_size) b->tail_pos = new_tail; -- cgit v1.2.3 From fd7826d56bde11ab142d2431093773ad2b3f0a59 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Fri, 26 Sep 2008 17:50:31 -0400 Subject: oprofile: implement switch/case in buffer_sync.c Signed-off-by: Robert Richter --- drivers/oprofile/buffer_sync.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) (limited to 'drivers/oprofile/buffer_sync.c') diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c index 774b081b9b7f..7d61ae8ee8cf 100644 --- a/drivers/oprofile/buffer_sync.c +++ b/drivers/oprofile/buffer_sync.c @@ -561,6 +561,7 @@ void sync_buffer(int cpu) { struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu); struct mm_struct *mm = NULL; + struct mm_struct *oldmm; struct task_struct *new; unsigned long cookie = 0; int in_kernel = 1; @@ -586,34 +587,39 @@ void sync_buffer(int cpu) struct op_sample *s = &cpu_buf->buffer[cpu_buf->tail_pos]; if (is_code(s->eip)) { - if (s->event <= CPU_IS_KERNEL) { + switch (s->event) { + case 0: + case CPU_IS_KERNEL: /* kernel/userspace switch */ in_kernel = s->event; if (state == sb_buffer_start) state = sb_sample_start; add_kernel_ctx_switch(s->event); - } else if (s->event == CPU_TRACE_BEGIN) { + break; + case CPU_TRACE_BEGIN: state = sb_bt_start; add_trace_begin(); + break; #ifdef CONFIG_OPROFILE_IBS - } else if (s->event == IBS_FETCH_BEGIN) { + case IBS_FETCH_BEGIN: state = sb_bt_start; add_ibs_begin(cpu_buf, IBS_FETCH_CODE, mm); - } else if (s->event == IBS_OP_BEGIN) { + break; + case IBS_OP_BEGIN: state = sb_bt_start; add_ibs_begin(cpu_buf, IBS_OP_CODE, mm); + break; #endif - } else { - struct mm_struct *oldmm = mm; - + default: /* userspace context switch */ + oldmm = mm; new = (struct task_struct *)s->event; - release_mm(oldmm); mm = take_tasks_mm(new); if (mm != oldmm) cookie = get_exec_dcookie(mm); add_user_ctx_switch(new, cookie); + break; } } else if (state >= sb_bt_start && !add_sample(mm, s, in_kernel)) { -- cgit v1.2.3 From 7d468abee0f1a7e918b5e2f23120436a54ba9f33 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Thu, 27 Nov 2008 10:57:09 +0100 Subject: oprofile: adding cpu buffer r/w access functions This is in preparation for changes in the cpu buffer implementation. Signed-off-by: Robert Richter --- drivers/oprofile/buffer_sync.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) (limited to 'drivers/oprofile/buffer_sync.c') diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c index 7d61ae8ee8cf..44f676c8a51d 100644 --- a/drivers/oprofile/buffer_sync.c +++ b/drivers/oprofile/buffer_sync.c @@ -331,10 +331,8 @@ static void add_trace_begin(void) #define IBS_FETCH_CODE_SIZE 2 #define IBS_OP_CODE_SIZE 5 -#define IBS_EIP(offset) \ - (((struct op_sample *)&cpu_buf->buffer[(offset)])->eip) -#define IBS_EVENT(offset) \ - (((struct op_sample *)&cpu_buf->buffer[(offset)])->event) +#define IBS_EIP(cpu_buf) ((cpu_buffer_read_entry(cpu_buf))->eip) +#define IBS_EVENT(cpu_buf) ((cpu_buffer_read_entry(cpu_buf))->event) /* * Add IBS fetch and op entries to event buffer @@ -349,10 +347,10 @@ static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, increment_tail(cpu_buf); /* move to RIP entry */ - rip = IBS_EIP(cpu_buf->tail_pos); + rip = IBS_EIP(cpu_buf); #ifdef __LP64__ - rip += IBS_EVENT(cpu_buf->tail_pos) << 32; + rip += IBS_EVENT(cpu_buf) << 32; #endif if (mm) { @@ -376,8 +374,8 @@ static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, add_event_entry(offset); /* Offset from Dcookie */ /* we send the Dcookie offset, but send the raw Linear Add also*/ - add_event_entry(IBS_EIP(cpu_buf->tail_pos)); - add_event_entry(IBS_EVENT(cpu_buf->tail_pos)); + add_event_entry(IBS_EIP(cpu_buf)); + add_event_entry(IBS_EVENT(cpu_buf)); if (code == IBS_FETCH_CODE) count = IBS_FETCH_CODE_SIZE; /*IBS FETCH is 2 int64s*/ @@ -386,8 +384,8 @@ static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, for (i = 0; i < count; i++) { increment_tail(cpu_buf); - add_event_entry(IBS_EIP(cpu_buf->tail_pos)); - add_event_entry(IBS_EVENT(cpu_buf->tail_pos)); + add_event_entry(IBS_EIP(cpu_buf)); + add_event_entry(IBS_EVENT(cpu_buf)); } } @@ -584,7 +582,7 @@ void sync_buffer(int cpu) #else while (get_slots(cpu_buf)) { #endif - struct op_sample *s = &cpu_buf->buffer[cpu_buf->tail_pos]; + struct op_sample *s = cpu_buffer_read_entry(cpu_buf); if (is_code(s->eip)) { switch (s->event) { -- cgit v1.2.3 From bf589e32960181fa8cbca7bfdd92265e49dc2dfa Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Thu, 27 Nov 2008 22:33:37 +0100 Subject: oprofile: adding cpu_buffer_entries() This is in preparation for changes in the cpu buffer implementation. Signed-off-by: Robert Richter --- drivers/oprofile/buffer_sync.c | 31 ++----------------------------- 1 file changed, 2 insertions(+), 29 deletions(-) (limited to 'drivers/oprofile/buffer_sync.c') diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c index 44f676c8a51d..aed286c3f16e 100644 --- a/drivers/oprofile/buffer_sync.c +++ b/drivers/oprofile/buffer_sync.c @@ -464,33 +464,6 @@ static inline int is_code(unsigned long val) } -/* "acquire" as many cpu buffer slots as we can */ -static unsigned long get_slots(struct oprofile_cpu_buffer *b) -{ - unsigned long head = b->head_pos; - unsigned long tail = b->tail_pos; - - /* - * Subtle. This resets the persistent last_task - * and in_kernel values used for switching notes. - * BUT, there is a small window between reading - * head_pos, and this call, that means samples - * can appear at the new head position, but not - * be prefixed with the notes for switching - * kernel mode or a task switch. This small hole - * can lead to mis-attribution or samples where - * we don't know if it's in the kernel or not, - * at the start of an event buffer. - */ - cpu_buffer_reset(b); - - if (head >= tail) - return head - tail; - - return head + (b->buffer_size - tail); -} - - /* Move tasks along towards death. Any tasks on dead_tasks * will definitely have no remaining references in any * CPU buffers at this point, because we use two lists, @@ -576,11 +549,11 @@ void sync_buffer(int cpu) /* Remember, only we can modify tail_pos */ #ifndef CONFIG_OPROFILE_IBS - available = get_slots(cpu_buf); + available = cpu_buffer_entries(cpu_buf); for (i = 0; i < available; ++i) { #else - while (get_slots(cpu_buf)) { + while (cpu_buffer_entries(cpu_buf)) { #endif struct op_sample *s = cpu_buffer_read_entry(cpu_buf); -- cgit v1.2.3 From fbc9bf9f0ed4f0fbc47dcb5b1c26c28c93b60e33 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Thu, 4 Dec 2008 16:27:00 +0100 Subject: oprofile: moving cpu_buffer_reset() to cpu_buffer.h This is in preparation for changes in the cpu buffer implementation. Signed-off-by: Robert Richter --- drivers/oprofile/buffer_sync.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/oprofile/buffer_sync.c') diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c index aed286c3f16e..944a5832d9e4 100644 --- a/drivers/oprofile/buffer_sync.c +++ b/drivers/oprofile/buffer_sync.c @@ -548,6 +548,7 @@ void sync_buffer(int cpu) /* Remember, only we can modify tail_pos */ + cpu_buffer_reset(cpu); #ifndef CONFIG_OPROFILE_IBS available = cpu_buffer_entries(cpu_buf); -- cgit v1.2.3 From 6dad828b76c7224a22ddc9ce7aa495d994f03b31 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Tue, 9 Dec 2008 01:21:32 +0100 Subject: oprofile: port to the new ring_buffer This patch replaces the current oprofile cpu buffer implementation with the ring buffer provided by the tracing framework. The motivation here is to leave the pain of implementing ring buffers to others. Oh, no, there are more advantages. Main reason is the support of different sample sizes that could be stored in the buffer. Use cases for this are IBS and Cell spu profiling. Using the new ring buffer ensures valid and complete samples and allows copying the cpu buffer stateless without knowing its content. Second it will use generic kernel API and also reduce code size. And hopefully, there are less bugs. Since the new tracing ring buffer implementation uses spin locks to protect the buffer during read/write access, it is difficult to use the buffer in an NMI handler. In this case, writing to the buffer by the NMI handler (x86) could occur also during critical sections when reading the buffer. To avoid this, there are 2 buffers for independent read and write access. Read access is in process context only, write access only in the NMI handler. If the read buffer runs empty, both buffers are swapped atomically. There is potentially a small window during swapping where the buffers are disabled and samples could be lost. Using 2 buffers is a little bit overhead, but the solution is clear and does not require changes in the ring buffer implementation. It can be changed to a single buffer solution when the ring buffer access is implemented as non-locking atomic code. The new buffer requires more size to store the same amount of samples because each sample includes an u32 header. Also, there is more code to execute for buffer access. Nonetheless, the buffer implementation is proven in the ftrace environment and worth to use also in oprofile. Patches that changes the internal IBS buffer usage will follow. Cc: Steven Rostedt Signed-off-by: Robert Richter --- drivers/oprofile/buffer_sync.c | 65 ++++++++++++++++-------------------------- 1 file changed, 25 insertions(+), 40 deletions(-) (limited to 'drivers/oprofile/buffer_sync.c') diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c index 944a5832d9e4..737bd9484822 100644 --- a/drivers/oprofile/buffer_sync.c +++ b/drivers/oprofile/buffer_sync.c @@ -268,18 +268,6 @@ lookup_dcookie(struct mm_struct *mm, unsigned long addr, off_t *offset) return cookie; } -static void increment_tail(struct oprofile_cpu_buffer *b) -{ - unsigned long new_tail = b->tail_pos + 1; - - rmb(); /* be sure fifo pointers are synchronized */ - - if (new_tail < b->buffer_size) - b->tail_pos = new_tail; - else - b->tail_pos = 0; -} - static unsigned long last_cookie = INVALID_COOKIE; static void add_cpu_switch(int i) @@ -331,26 +319,25 @@ static void add_trace_begin(void) #define IBS_FETCH_CODE_SIZE 2 #define IBS_OP_CODE_SIZE 5 -#define IBS_EIP(cpu_buf) ((cpu_buffer_read_entry(cpu_buf))->eip) -#define IBS_EVENT(cpu_buf) ((cpu_buffer_read_entry(cpu_buf))->event) /* * Add IBS fetch and op entries to event buffer */ -static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, - struct mm_struct *mm) +static void add_ibs_begin(int cpu, int code, struct mm_struct *mm) { unsigned long rip; int i, count; unsigned long ibs_cookie = 0; off_t offset; + struct op_sample *sample; - increment_tail(cpu_buf); /* move to RIP entry */ - - rip = IBS_EIP(cpu_buf); + sample = cpu_buffer_read_entry(cpu); + if (!sample) + goto Error; + rip = sample->eip; #ifdef __LP64__ - rip += IBS_EVENT(cpu_buf) << 32; + rip += sample->event << 32; #endif if (mm) { @@ -374,8 +361,8 @@ static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, add_event_entry(offset); /* Offset from Dcookie */ /* we send the Dcookie offset, but send the raw Linear Add also*/ - add_event_entry(IBS_EIP(cpu_buf)); - add_event_entry(IBS_EVENT(cpu_buf)); + add_event_entry(sample->eip); + add_event_entry(sample->event); if (code == IBS_FETCH_CODE) count = IBS_FETCH_CODE_SIZE; /*IBS FETCH is 2 int64s*/ @@ -383,10 +370,17 @@ static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, count = IBS_OP_CODE_SIZE; /*IBS OP is 5 int64s*/ for (i = 0; i < count; i++) { - increment_tail(cpu_buf); - add_event_entry(IBS_EIP(cpu_buf)); - add_event_entry(IBS_EVENT(cpu_buf)); + sample = cpu_buffer_read_entry(cpu); + if (!sample) + goto Error; + add_event_entry(sample->eip); + add_event_entry(sample->event); } + + return; + +Error: + return; } #endif @@ -530,33 +524,26 @@ typedef enum { */ void sync_buffer(int cpu) { - struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu); struct mm_struct *mm = NULL; struct mm_struct *oldmm; struct task_struct *new; unsigned long cookie = 0; int in_kernel = 1; sync_buffer_state state = sb_buffer_start; -#ifndef CONFIG_OPROFILE_IBS unsigned int i; unsigned long available; -#endif mutex_lock(&buffer_mutex); add_cpu_switch(cpu); - /* Remember, only we can modify tail_pos */ - cpu_buffer_reset(cpu); -#ifndef CONFIG_OPROFILE_IBS - available = cpu_buffer_entries(cpu_buf); + available = cpu_buffer_entries(cpu); for (i = 0; i < available; ++i) { -#else - while (cpu_buffer_entries(cpu_buf)) { -#endif - struct op_sample *s = cpu_buffer_read_entry(cpu_buf); + struct op_sample *s = cpu_buffer_read_entry(cpu); + if (!s) + break; if (is_code(s->eip)) { switch (s->event) { @@ -575,11 +562,11 @@ void sync_buffer(int cpu) #ifdef CONFIG_OPROFILE_IBS case IBS_FETCH_BEGIN: state = sb_bt_start; - add_ibs_begin(cpu_buf, IBS_FETCH_CODE, mm); + add_ibs_begin(cpu, IBS_FETCH_CODE, mm); break; case IBS_OP_BEGIN: state = sb_bt_start; - add_ibs_begin(cpu_buf, IBS_OP_CODE, mm); + add_ibs_begin(cpu, IBS_OP_CODE, mm); break; #endif default: @@ -600,8 +587,6 @@ void sync_buffer(int cpu) atomic_inc(&oprofile_stats.bt_lost_no_mapping); } } - - increment_tail(cpu_buf); } release_mm(mm); -- cgit v1.2.3