lib/profiler/get_tick.h

   1 /*
   2  * Copyright (C) 1996-2018 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef _PROFILER_GET_TICK_H_
  10 #define _PROFILER_GET_TICK_H_
  11
  12 #if USE_XPROF_STATS
  13
  14 /*
  15  * Ensure that any changes here are synchronised with SQUID_CHECK_FUNCTIONAL_CPU_PROFILER
  16  */
  17
  18 #if !_SQUID_SOLARIS_
  19 typedef int64_t  hrtime_t;
  20 #endif
  21
  22 #if defined(__GNUC__) && ( defined(__i386) || defined(__i386__) )
  23 static inline hrtime_t
  24 get_tick(void)
  25 {
  26     hrtime_t regs;
  27
  28     asm volatile ("rdtsc":"=A" (regs));
  29     return regs;
  30     /* We need return value, we rely on CC to optimise out needless subf calls */
  31     /* Note that "rdtsc" is relatively slow OP and stalls the CPU pipes, so use it wisely */
  32 }
  33
  34 #elif defined(__GNUC__) && ( defined(__x86_64) || defined(__x86_64__) )
  35 static inline hrtime_t
  36 get_tick(void)
  37 {
  38     uint32_t lo, hi;
  39     // Based on an example in Wikipedia
  40     /* We cannot use "=A", since this would use %rax on x86_64 */
  41     asm volatile ("rdtsc" : "=a" (lo), "=d" (hi));
  42     return (hrtime_t)hi << 32 | lo;
  43 }
  44
  45 #elif defined(__GNUC__) && defined(__alpha)
  46 static inline hrtime_t
  47 get_tick(void)
  48 {
  49     hrtime_t regs;
  50
  51     asm volatile ("rpcc %0" : "=r" (regs));
  52     return regs;
  53 }
  54
  55 #elif defined(_M_IX86) && defined(_MSC_VER) /* x86 platform on Microsoft C Compiler ONLY */
  56 static __inline hrtime_t
  57 get_tick(void)
  58 {
  59     hrtime_t regs;
  60
  61     __asm {
  62         cpuid
  63         rdtsc
  64         mov eax,DWORD PTR regs[0]
  65         mov edx,DWORD PTR regs[4]
  66     }
  67     return regs;
  68 }
  69
  70 #else
  71 /* This CPU is unsupported. Short-circuit, no profiling here */
  72 // #error for configure tests to prevent library construction
  73 #error This CPU is unsupported. No profiling available here.
  74 #endif
  75
  76 #endif /* USE_XPROF_STATS */
  77 #endif /* _PROFILING_H_ */
  78