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912e603778
looking at a high resolution clock for each of the following events: function call, function return, interrupt entry, interrupt exit, and interesting branches. The differences between the times of these events are added at appropriate places in a ordinary histogram (as if very fast statistical profiling sampled the pc at those places) so that ordinary gprof can be used to analyze the times. gmon.h: Histogram counters need to be 4 bytes for microsecond resolutions. They will need to be larger for the 586 clock. The comments were vax-centric and wrong even on vaxes. Does anyone disagree? gprof4.c: The standard gprof should support counters of all integral sizes and the size of the counter should be in the gmon header. This hack will do until then. (Use gprof4 -u to examine the results of non-statistical profiling.) config/*: Non-statistical profiling is configured with `config -pp'. `config -p' still gives ordinary profiling. kgmon/*: Non-statistical profiling is enabled with `kgmon -B'. `kgmon -b' still enables ordinary profiling (and distables non-statistical profiling) if non-statistical profiling is configured.
154 lines
3.0 KiB
C
154 lines
3.0 KiB
C
#include <sys/param.h>
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#include <sys/systm.h>
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#include <machine/clock.h>
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#include <i386/isa/isa.h>
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#include <i386/isa/timerreg.h>
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#ifdef GUPROF
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extern u_int cputime __P((void));
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#endif
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#ifdef __GNUC__
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asm("
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GM_STATE = 0
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GMON_PROF_OFF = 3
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.text
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.align 4,0x90
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.globl __mcount
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__mcount:
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#
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# Check that we are profiling. Do it early for speed.
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#
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cmpl $GMON_PROF_OFF,__gmonparam+GM_STATE
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je Lmcount_exit
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#
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# __mcount is the same as mcount except the caller hasn't changed
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# the stack except to call here, so the caller's raddr is above
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# our raddr.
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#
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movl 4(%esp),%edx
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jmp Lgot_frompc
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.align 4,0x90
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.globl mcount
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mcount:
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cmpl $GMON_PROF_OFF,__gmonparam+GM_STATE
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je Lmcount_exit
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#
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# The caller's stack frame has already been built, so %ebp is
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# the caller's frame pointer. The caller's raddr is in the
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# caller's frame following the caller's caller's frame pointer.
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#
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movl 4(%ebp),%edx
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Lgot_frompc:
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#
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# Our raddr is the caller's pc.
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#
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movl (%esp),%eax
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pushf
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pushl %eax
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pushl %edx
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cli
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call _mcount
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addl $8,%esp
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popf
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Lmcount_exit:
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ret
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");
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#else /* !__GNUC__ */
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#error
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#endif /* __GNUC__ */
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#ifdef GUPROF
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/*
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* mexitcount saves the return register(s), loads selfpc and calls
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* mexitcount(selfpc) to do the work. Someday it should be in a machine
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* dependent file together with cputime(), __mcount and mcount. cputime()
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* can't just be put in machdep.c because it has to be compiled without -pg.
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*/
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#ifdef __GNUC__
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asm("
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.text
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#
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# Dummy label to be seen when gprof -u hides mexitcount.
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#
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.align 4,0x90
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.globl __mexitcount
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__mexitcount:
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nop
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GMON_PROF_HIRES = 4
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.align 4,0x90
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.globl mexitcount
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mexitcount:
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cmpl $GMON_PROF_HIRES,__gmonparam+GM_STATE
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jne Lmexitcount_exit
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pushl %edx
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pushl %eax
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movl 8(%esp),%eax
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pushf
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pushl %eax
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cli
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call _mexitcount
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addl $4,%esp
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popf
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popl %eax
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popl %edx
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Lmexitcount_exit:
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ret
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");
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#else /* !__GNUC__ */
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#error
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#endif /* __GNUC__ */
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/*
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* Return the time elapsed since the last call. The units are machine-
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* dependent.
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*/
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u_int
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cputime()
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{
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u_int count;
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u_int delta;
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u_char low;
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static u_int prev_count;
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/*
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* Read the current value of the 8254 timer counter 0.
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*/
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outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
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low = inb(TIMER_CNTR0);
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count = low | (inb(TIMER_CNTR0) << 8);
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/*
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* The timer counts down from TIMER_CNTR0_MAX to 0 and then resets.
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* While profiling is enabled, this routine is called at least twice
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* per timer reset (for mcounting and mexitcounting hardclock()),
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* so at most one reset has occurred since the last call, and one
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* has occurred iff the current count is larger than the previous
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* count. This allows counter underflow to be detected faster
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* than in microtime().
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*/
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delta = prev_count - count;
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prev_count = count;
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if ((int) delta <= 0)
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return (delta + timer0_max_count);
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return (delta);
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}
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#else /* not GUPROF */
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#ifdef __GNUC__
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asm("
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.text
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.align 4,0x90
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.globl mexitcount
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mexitcount:
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ret
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");
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#else /* !__GNUC__ */
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#error
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#endif /* __GNUC__ */
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#endif /* GUPROF */
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