cosmopolitan/libc/runtime/ftracer.c
Justine Tunney 9208c83f7a Make some systemic improvements
- add vdso dump utility
- tests now log stack usage
- rename g_ftrace to __ftrace
- make internal spinlocks go faster
- add conformant c11 atomics library
- function tracing now logs stack usage
- make function call tracing thread safe
- add -X unsecure (no ssl) mode to redbean
- munmap() has more consistent behavior now
- pacify fsync() calls on python unit tests
- make --strace flag work better in redbean
- start minimizing and documenting compiler flags
2022-05-18 16:52:36 -07:00

114 lines
4.5 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/safemacros.internal.h"
#include "libc/fmt/itoa.h"
#include "libc/intrin/cmpxchg.h"
#include "libc/intrin/kprintf.h"
#include "libc/intrin/spinlock.h"
#include "libc/log/libfatal.internal.h"
#include "libc/macros.internal.h"
#include "libc/math.h"
#include "libc/nexgen32e/rdtsc.h"
#include "libc/nexgen32e/rdtscp.h"
#include "libc/nexgen32e/stackframe.h"
#include "libc/nexgen32e/x86feature.h"
#include "libc/runtime/memtrack.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/stack.h"
#include "libc/runtime/symbols.internal.h"
#include "libc/stdio/stdio.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/time/clockstonanos.internal.h"
#define MAX_NESTING 512
/**
* @fileoverview Plain-text function call logging.
*
* Able to log ~2 million function calls per second, which is mostly
* bottlenecked by system call overhead. Log size is reasonable if piped
* into gzip.
*/
void ftrace_hook(void);
_Alignas(64) char ftrace_lock;
static struct Ftrace {
int skew;
int stackdigs;
int64_t lastaddr;
uint64_t laststamp;
} g_ftrace;
static privileged int GetNestingLevelImpl(struct StackFrame *frame) {
int nesting = -2;
while (frame) {
++nesting;
frame = frame->next;
}
return MAX(0, nesting);
}
static privileged int GetNestingLevel(struct StackFrame *frame) {
int nesting;
nesting = GetNestingLevelImpl(frame);
if (nesting < g_ftrace.skew) g_ftrace.skew = nesting;
nesting -= g_ftrace.skew;
return MIN(MAX_NESTING, nesting);
}
/**
* Prints name of function being called.
*
* We insert CALL instructions that point to this function, in the
* prologues of other functions. We assume those functions behave
* according to the System Five NexGen32e ABI.
*/
privileged void ftracer(void) {
uint64_t stamp;
size_t stackuse;
struct StackFrame *frame;
_spinlock_cooperative(&ftrace_lock);
stamp = rdtsc();
frame = __builtin_frame_address(0);
frame = frame->next;
if (frame->addr != g_ftrace.lastaddr) {
stackuse = ROUNDUP((intptr_t)frame, GetStackSize()) - (intptr_t)frame;
kprintf("%rFUN %5P %'13T %'*lu %*s%t\r\n", g_ftrace.stackdigs, stackuse,
GetNestingLevel(frame) * 2, "", frame->addr);
g_ftrace.laststamp = X86_HAVE(RDTSCP) ? rdtscp(0) : rdtsc();
g_ftrace.lastaddr = frame->addr;
}
_spunlock(&ftrace_lock);
}
textstartup int ftrace_install(void) {
if (GetSymbolTable()) {
g_ftrace.lastaddr = -1;
g_ftrace.laststamp = kStartTsc;
g_ftrace.stackdigs = LengthInt64Thousands(GetStackSize());
g_ftrace.skew = GetNestingLevelImpl(__builtin_frame_address(0));
return __hook(ftrace_hook, GetSymbolTable());
} else {
kprintf("error: --ftrace failed to open symbol table\r\n");
return -1;
}
}