From: Adrian Hunter Date: Thu, 30 Oct 2014 14:09:45 +0000 (+0200) Subject: perf tools: Enhance the thread stack to output call/return data X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=92a9e4f7db89a013e1bdef2e548928fc71e9867c;p=openwrt%2Fstaging%2Fblogic.git perf tools: Enhance the thread stack to output call/return data Enhance the thread stack to output detailed information about paired calls and returns. The enhanced processing consumes sample information via thread_stack__process() and outputs information about paired calls / returns via a call-back. While the call-back makes it possible for the facility to be used by arbitrary tools, a subsequent patch will provide the information to Python scripting via the db-export interface. An important part of the call/return information is the call path which provides a structure that defines a context sensitive call graph. Note that there are now two ways to use the thread stack. For simply providing a call stack (like you would get from the perf record -g option) the interface consists of thread_stack__event() and thread_stack__sample(). Whereas the enhanced interface consists of call_return_processor__new() and thread_stack__process(). Signed-off-by: Adrian Hunter Acked-by: Jiri Olsa Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/r/1414678188-14946-5-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c index 85b60d2e738f..9ed59a452d1f 100644 --- a/tools/perf/util/thread-stack.c +++ b/tools/perf/util/thread-stack.c @@ -13,23 +13,96 @@ * */ +#include +#include #include "thread.h" #include "event.h" +#include "machine.h" #include "util.h" #include "debug.h" +#include "symbol.h" +#include "comm.h" #include "thread-stack.h" -#define STACK_GROWTH 4096 +#define CALL_PATH_BLOCK_SHIFT 8 +#define CALL_PATH_BLOCK_SIZE (1 << CALL_PATH_BLOCK_SHIFT) +#define CALL_PATH_BLOCK_MASK (CALL_PATH_BLOCK_SIZE - 1) +struct call_path_block { + struct call_path cp[CALL_PATH_BLOCK_SIZE]; + struct list_head node; +}; + +/** + * struct call_path_root - root of all call paths. + * @call_path: root call path + * @blocks: list of blocks to store call paths + * @next: next free space + * @sz: number of spaces + */ +struct call_path_root { + struct call_path call_path; + struct list_head blocks; + size_t next; + size_t sz; +}; + +/** + * struct call_return_processor - provides a call-back to consume call-return + * information. + * @cpr: call path root + * @process: call-back that accepts call/return information + * @data: anonymous data for call-back + */ +struct call_return_processor { + struct call_path_root *cpr; + int (*process)(struct call_return *cr, void *data); + void *data; +}; + +#define STACK_GROWTH 2048 + +/** + * struct thread_stack_entry - thread stack entry. + * @ret_addr: return address + * @timestamp: timestamp (if known) + * @ref: external reference (e.g. db_id of sample) + * @branch_count: the branch count when the entry was created + * @cp: call path + * @no_call: a 'call' was not seen + */ struct thread_stack_entry { u64 ret_addr; + u64 timestamp; + u64 ref; + u64 branch_count; + struct call_path *cp; + bool no_call; }; +/** + * struct thread_stack - thread stack constructed from 'call' and 'return' + * branch samples. + * @stack: array that holds the stack + * @cnt: number of entries in the stack + * @sz: current maximum stack size + * @trace_nr: current trace number + * @branch_count: running branch count + * @kernel_start: kernel start address + * @last_time: last timestamp + * @crp: call/return processor + * @comm: current comm + */ struct thread_stack { struct thread_stack_entry *stack; size_t cnt; size_t sz; u64 trace_nr; + u64 branch_count; + u64 kernel_start; + u64 last_time; + struct call_return_processor *crp; + struct comm *comm; }; static int thread_stack__grow(struct thread_stack *ts) @@ -50,7 +123,8 @@ static int thread_stack__grow(struct thread_stack *ts) return 0; } -static struct thread_stack *thread_stack__new(void) +static struct thread_stack *thread_stack__new(struct thread *thread, + struct call_return_processor *crp) { struct thread_stack *ts; @@ -63,6 +137,12 @@ static struct thread_stack *thread_stack__new(void) return NULL; } + if (thread->mg && thread->mg->machine) + ts->kernel_start = machine__kernel_start(thread->mg->machine); + else + ts->kernel_start = 1ULL << 63; + ts->crp = crp; + return ts; } @@ -104,6 +184,64 @@ static void thread_stack__pop(struct thread_stack *ts, u64 ret_addr) } } +static bool thread_stack__in_kernel(struct thread_stack *ts) +{ + if (!ts->cnt) + return false; + + return ts->stack[ts->cnt - 1].cp->in_kernel; +} + +static int thread_stack__call_return(struct thread *thread, + struct thread_stack *ts, size_t idx, + u64 timestamp, u64 ref, bool no_return) +{ + struct call_return_processor *crp = ts->crp; + struct thread_stack_entry *tse; + struct call_return cr = { + .thread = thread, + .comm = ts->comm, + .db_id = 0, + }; + + tse = &ts->stack[idx]; + cr.cp = tse->cp; + cr.call_time = tse->timestamp; + cr.return_time = timestamp; + cr.branch_count = ts->branch_count - tse->branch_count; + cr.call_ref = tse->ref; + cr.return_ref = ref; + if (tse->no_call) + cr.flags |= CALL_RETURN_NO_CALL; + if (no_return) + cr.flags |= CALL_RETURN_NO_RETURN; + + return crp->process(&cr, crp->data); +} + +static int thread_stack__flush(struct thread *thread, struct thread_stack *ts) +{ + struct call_return_processor *crp = ts->crp; + int err; + + if (!crp) { + ts->cnt = 0; + return 0; + } + + while (ts->cnt) { + err = thread_stack__call_return(thread, ts, --ts->cnt, + ts->last_time, 0, true); + if (err) { + pr_err("Error flushing thread stack!\n"); + ts->cnt = 0; + return err; + } + } + + return 0; +} + int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip, u64 to_ip, u16 insn_len, u64 trace_nr) { @@ -111,7 +249,7 @@ int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip, return -EINVAL; if (!thread->ts) { - thread->ts = thread_stack__new(); + thread->ts = thread_stack__new(thread, NULL); if (!thread->ts) { pr_warning("Out of memory: no thread stack\n"); return -ENOMEM; @@ -122,13 +260,18 @@ int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip, /* * When the trace is discontinuous, the trace_nr changes. In that case * the stack might be completely invalid. Better to report nothing than - * to report something misleading, so reset the stack count to zero. + * to report something misleading, so flush the stack. */ if (trace_nr != thread->ts->trace_nr) { + if (thread->ts->trace_nr) + thread_stack__flush(thread, thread->ts); thread->ts->trace_nr = trace_nr; - thread->ts->cnt = 0; } + /* Stop here if thread_stack__process() is in use */ + if (thread->ts->crp) + return 0; + if (flags & PERF_IP_FLAG_CALL) { u64 ret_addr; @@ -147,9 +290,22 @@ int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip, return 0; } +void thread_stack__set_trace_nr(struct thread *thread, u64 trace_nr) +{ + if (!thread || !thread->ts) + return; + + if (trace_nr != thread->ts->trace_nr) { + if (thread->ts->trace_nr) + thread_stack__flush(thread, thread->ts); + thread->ts->trace_nr = trace_nr; + } +} + void thread_stack__free(struct thread *thread) { if (thread->ts) { + thread_stack__flush(thread, thread->ts); zfree(&thread->ts->stack); zfree(&thread->ts); } @@ -170,3 +326,422 @@ void thread_stack__sample(struct thread *thread, struct ip_callchain *chain, for (i = 1; i < chain->nr; i++) chain->ips[i] = thread->ts->stack[thread->ts->cnt - i].ret_addr; } + +static void call_path__init(struct call_path *cp, struct call_path *parent, + struct symbol *sym, u64 ip, bool in_kernel) +{ + cp->parent = parent; + cp->sym = sym; + cp->ip = sym ? 0 : ip; + cp->db_id = 0; + cp->in_kernel = in_kernel; + RB_CLEAR_NODE(&cp->rb_node); + cp->children = RB_ROOT; +} + +static struct call_path_root *call_path_root__new(void) +{ + struct call_path_root *cpr; + + cpr = zalloc(sizeof(struct call_path_root)); + if (!cpr) + return NULL; + call_path__init(&cpr->call_path, NULL, NULL, 0, false); + INIT_LIST_HEAD(&cpr->blocks); + return cpr; +} + +static void call_path_root__free(struct call_path_root *cpr) +{ + struct call_path_block *pos, *n; + + list_for_each_entry_safe(pos, n, &cpr->blocks, node) { + list_del(&pos->node); + free(pos); + } + free(cpr); +} + +static struct call_path *call_path__new(struct call_path_root *cpr, + struct call_path *parent, + struct symbol *sym, u64 ip, + bool in_kernel) +{ + struct call_path_block *cpb; + struct call_path *cp; + size_t n; + + if (cpr->next < cpr->sz) { + cpb = list_last_entry(&cpr->blocks, struct call_path_block, + node); + } else { + cpb = zalloc(sizeof(struct call_path_block)); + if (!cpb) + return NULL; + list_add_tail(&cpb->node, &cpr->blocks); + cpr->sz += CALL_PATH_BLOCK_SIZE; + } + + n = cpr->next++ & CALL_PATH_BLOCK_MASK; + cp = &cpb->cp[n]; + + call_path__init(cp, parent, sym, ip, in_kernel); + + return cp; +} + +static struct call_path *call_path__findnew(struct call_path_root *cpr, + struct call_path *parent, + struct symbol *sym, u64 ip, u64 ks) +{ + struct rb_node **p; + struct rb_node *node_parent = NULL; + struct call_path *cp; + bool in_kernel = ip >= ks; + + if (sym) + ip = 0; + + if (!parent) + return call_path__new(cpr, parent, sym, ip, in_kernel); + + p = &parent->children.rb_node; + while (*p != NULL) { + node_parent = *p; + cp = rb_entry(node_parent, struct call_path, rb_node); + + if (cp->sym == sym && cp->ip == ip) + return cp; + + if (sym < cp->sym || (sym == cp->sym && ip < cp->ip)) + p = &(*p)->rb_left; + else + p = &(*p)->rb_right; + } + + cp = call_path__new(cpr, parent, sym, ip, in_kernel); + if (!cp) + return NULL; + + rb_link_node(&cp->rb_node, node_parent, p); + rb_insert_color(&cp->rb_node, &parent->children); + + return cp; +} + +struct call_return_processor * +call_return_processor__new(int (*process)(struct call_return *cr, void *data), + void *data) +{ + struct call_return_processor *crp; + + crp = zalloc(sizeof(struct call_return_processor)); + if (!crp) + return NULL; + crp->cpr = call_path_root__new(); + if (!crp->cpr) + goto out_free; + crp->process = process; + crp->data = data; + return crp; + +out_free: + free(crp); + return NULL; +} + +void call_return_processor__free(struct call_return_processor *crp) +{ + if (crp) { + call_path_root__free(crp->cpr); + free(crp); + } +} + +static int thread_stack__push_cp(struct thread_stack *ts, u64 ret_addr, + u64 timestamp, u64 ref, struct call_path *cp, + bool no_call) +{ + struct thread_stack_entry *tse; + int err; + + if (ts->cnt == ts->sz) { + err = thread_stack__grow(ts); + if (err) + return err; + } + + tse = &ts->stack[ts->cnt++]; + tse->ret_addr = ret_addr; + tse->timestamp = timestamp; + tse->ref = ref; + tse->branch_count = ts->branch_count; + tse->cp = cp; + tse->no_call = no_call; + + return 0; +} + +static int thread_stack__pop_cp(struct thread *thread, struct thread_stack *ts, + u64 ret_addr, u64 timestamp, u64 ref, + struct symbol *sym) +{ + int err; + + if (!ts->cnt) + return 1; + + if (ts->cnt == 1) { + struct thread_stack_entry *tse = &ts->stack[0]; + + if (tse->cp->sym == sym) + return thread_stack__call_return(thread, ts, --ts->cnt, + timestamp, ref, false); + } + + if (ts->stack[ts->cnt - 1].ret_addr == ret_addr) { + return thread_stack__call_return(thread, ts, --ts->cnt, + timestamp, ref, false); + } else { + size_t i = ts->cnt - 1; + + while (i--) { + if (ts->stack[i].ret_addr != ret_addr) + continue; + i += 1; + while (ts->cnt > i) { + err = thread_stack__call_return(thread, ts, + --ts->cnt, + timestamp, ref, + true); + if (err) + return err; + } + return thread_stack__call_return(thread, ts, --ts->cnt, + timestamp, ref, false); + } + } + + return 1; +} + +static int thread_stack__bottom(struct thread *thread, struct thread_stack *ts, + struct perf_sample *sample, + struct addr_location *from_al, + struct addr_location *to_al, u64 ref) +{ + struct call_path_root *cpr = ts->crp->cpr; + struct call_path *cp; + struct symbol *sym; + u64 ip; + + if (sample->ip) { + ip = sample->ip; + sym = from_al->sym; + } else if (sample->addr) { + ip = sample->addr; + sym = to_al->sym; + } else { + return 0; + } + + cp = call_path__findnew(cpr, &cpr->call_path, sym, ip, + ts->kernel_start); + if (!cp) + return -ENOMEM; + + return thread_stack__push_cp(thread->ts, ip, sample->time, ref, cp, + true); +} + +static int thread_stack__no_call_return(struct thread *thread, + struct thread_stack *ts, + struct perf_sample *sample, + struct addr_location *from_al, + struct addr_location *to_al, u64 ref) +{ + struct call_path_root *cpr = ts->crp->cpr; + struct call_path *cp, *parent; + u64 ks = ts->kernel_start; + int err; + + if (sample->ip >= ks && sample->addr < ks) { + /* Return to userspace, so pop all kernel addresses */ + while (thread_stack__in_kernel(ts)) { + err = thread_stack__call_return(thread, ts, --ts->cnt, + sample->time, ref, + true); + if (err) + return err; + } + + /* If the stack is empty, push the userspace address */ + if (!ts->cnt) { + cp = call_path__findnew(cpr, &cpr->call_path, + to_al->sym, sample->addr, + ts->kernel_start); + if (!cp) + return -ENOMEM; + return thread_stack__push_cp(ts, 0, sample->time, ref, + cp, true); + } + } else if (thread_stack__in_kernel(ts) && sample->ip < ks) { + /* Return to userspace, so pop all kernel addresses */ + while (thread_stack__in_kernel(ts)) { + err = thread_stack__call_return(thread, ts, --ts->cnt, + sample->time, ref, + true); + if (err) + return err; + } + } + + if (ts->cnt) + parent = ts->stack[ts->cnt - 1].cp; + else + parent = &cpr->call_path; + + /* This 'return' had no 'call', so push and pop top of stack */ + cp = call_path__findnew(cpr, parent, from_al->sym, sample->ip, + ts->kernel_start); + if (!cp) + return -ENOMEM; + + err = thread_stack__push_cp(ts, sample->addr, sample->time, ref, cp, + true); + if (err) + return err; + + return thread_stack__pop_cp(thread, ts, sample->addr, sample->time, ref, + to_al->sym); +} + +static int thread_stack__trace_begin(struct thread *thread, + struct thread_stack *ts, u64 timestamp, + u64 ref) +{ + struct thread_stack_entry *tse; + int err; + + if (!ts->cnt) + return 0; + + /* Pop trace end */ + tse = &ts->stack[ts->cnt - 1]; + if (tse->cp->sym == NULL && tse->cp->ip == 0) { + err = thread_stack__call_return(thread, ts, --ts->cnt, + timestamp, ref, false); + if (err) + return err; + } + + return 0; +} + +static int thread_stack__trace_end(struct thread_stack *ts, + struct perf_sample *sample, u64 ref) +{ + struct call_path_root *cpr = ts->crp->cpr; + struct call_path *cp; + u64 ret_addr; + + /* No point having 'trace end' on the bottom of the stack */ + if (!ts->cnt || (ts->cnt == 1 && ts->stack[0].ref == ref)) + return 0; + + cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp, NULL, 0, + ts->kernel_start); + if (!cp) + return -ENOMEM; + + ret_addr = sample->ip + sample->insn_len; + + return thread_stack__push_cp(ts, ret_addr, sample->time, ref, cp, + false); +} + +int thread_stack__process(struct thread *thread, struct comm *comm, + struct perf_sample *sample, + struct addr_location *from_al, + struct addr_location *to_al, u64 ref, + struct call_return_processor *crp) +{ + struct thread_stack *ts = thread->ts; + int err = 0; + + if (ts) { + if (!ts->crp) { + /* Supersede thread_stack__event() */ + thread_stack__free(thread); + thread->ts = thread_stack__new(thread, crp); + if (!thread->ts) + return -ENOMEM; + ts = thread->ts; + ts->comm = comm; + } + } else { + thread->ts = thread_stack__new(thread, crp); + if (!thread->ts) + return -ENOMEM; + ts = thread->ts; + ts->comm = comm; + } + + /* Flush stack on exec */ + if (ts->comm != comm && thread->pid_ == thread->tid) { + err = thread_stack__flush(thread, ts); + if (err) + return err; + ts->comm = comm; + } + + /* If the stack is empty, put the current symbol on the stack */ + if (!ts->cnt) { + err = thread_stack__bottom(thread, ts, sample, from_al, to_al, + ref); + if (err) + return err; + } + + ts->branch_count += 1; + ts->last_time = sample->time; + + if (sample->flags & PERF_IP_FLAG_CALL) { + struct call_path_root *cpr = ts->crp->cpr; + struct call_path *cp; + u64 ret_addr; + + if (!sample->ip || !sample->addr) + return 0; + + ret_addr = sample->ip + sample->insn_len; + if (ret_addr == sample->addr) + return 0; /* Zero-length calls are excluded */ + + cp = call_path__findnew(cpr, ts->stack[ts->cnt - 1].cp, + to_al->sym, sample->addr, + ts->kernel_start); + if (!cp) + return -ENOMEM; + err = thread_stack__push_cp(ts, ret_addr, sample->time, ref, + cp, false); + } else if (sample->flags & PERF_IP_FLAG_RETURN) { + if (!sample->ip || !sample->addr) + return 0; + + err = thread_stack__pop_cp(thread, ts, sample->addr, + sample->time, ref, from_al->sym); + if (err) { + if (err < 0) + return err; + err = thread_stack__no_call_return(thread, ts, sample, + from_al, to_al, ref); + } + } else if (sample->flags & PERF_IP_FLAG_TRACE_BEGIN) { + err = thread_stack__trace_begin(thread, ts, sample->time, ref); + } else if (sample->flags & PERF_IP_FLAG_TRACE_END) { + err = thread_stack__trace_end(ts, sample, ref); + } + + return err; +} diff --git a/tools/perf/util/thread-stack.h b/tools/perf/util/thread-stack.h index 7c41579aec74..b843bbef8ba2 100644 --- a/tools/perf/util/thread-stack.h +++ b/tools/perf/util/thread-stack.h @@ -19,14 +19,93 @@ #include #include +#include struct thread; +struct comm; struct ip_callchain; +struct symbol; +struct dso; +struct call_return_processor; +struct comm; +struct perf_sample; +struct addr_location; + +/* + * Call/Return flags. + * + * CALL_RETURN_NO_CALL: 'return' but no matching 'call' + * CALL_RETURN_NO_RETURN: 'call' but no matching 'return' + */ +enum { + CALL_RETURN_NO_CALL = 1 << 0, + CALL_RETURN_NO_RETURN = 1 << 1, +}; + +/** + * struct call_return - paired call/return information. + * @thread: thread in which call/return occurred + * @comm: comm in which call/return occurred + * @cp: call path + * @call_time: timestamp of call (if known) + * @return_time: timestamp of return (if known) + * @branch_count: number of branches seen between call and return + * @call_ref: external reference to 'call' sample (e.g. db_id) + * @return_ref: external reference to 'return' sample (e.g. db_id) + * @db_id: id used for db-export + * @flags: Call/Return flags + */ +struct call_return { + struct thread *thread; + struct comm *comm; + struct call_path *cp; + u64 call_time; + u64 return_time; + u64 branch_count; + u64 call_ref; + u64 return_ref; + u64 db_id; + u32 flags; +}; + +/** + * struct call_path - node in list of calls leading to a function call. + * @parent: call path to the parent function call + * @sym: symbol of function called + * @ip: only if sym is null, the ip of the function + * @db_id: id used for db-export + * @in_kernel: whether function is a in the kernel + * @rb_node: node in parent's tree of called functions + * @children: tree of call paths of functions called + * + * In combination with the call_return structure, the call_path structure + * defines a context-sensitve call-graph. + */ +struct call_path { + struct call_path *parent; + struct symbol *sym; + u64 ip; + u64 db_id; + bool in_kernel; + struct rb_node rb_node; + struct rb_root children; +}; int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip, u64 to_ip, u16 insn_len, u64 trace_nr); +void thread_stack__set_trace_nr(struct thread *thread, u64 trace_nr); void thread_stack__sample(struct thread *thread, struct ip_callchain *chain, size_t sz, u64 ip); void thread_stack__free(struct thread *thread); +struct call_return_processor * +call_return_processor__new(int (*process)(struct call_return *cr, void *data), + void *data); +void call_return_processor__free(struct call_return_processor *crp); +int thread_stack__process(struct thread *thread, struct comm *comm, + struct perf_sample *sample, + struct addr_location *from_al, + struct addr_location *to_al, u64 ref, + struct call_return_processor *crp); + #endif