ref: 164a8549ca6e5138b57aba6d68445245ba1391ea
dir: /sys/include/dtracy.h/
#pragma lib "libdtracy.a"
#pragma src "/sys/src/libdtracy"
/*
triggered probes run in "probe context", which involves grabbing a per-CPU lock using dtmachlock/dtmachunlock.
everything else in the library assumes that the calling code has grabbed a global lock (which is done in 9/port/devtracy.c).
*/
enum {
DTSTRMAX = 256,
DTRECMAX = 1024,
DTMAXAGGBUF = 16,
DTBUFSZ = 65536,
DTANUMBUCKETS = 1024,
DTABUCKETS = DTBUFSZ - 4 * DTANUMBUCKETS,
};
#define DTANIL ((u32int)-1)
typedef struct DTProbe DTProbe;
typedef struct DTExprState DTExprState;
typedef struct DTAct DTAct;
typedef struct DTActGr DTActGr;
typedef struct DTClause DTClause;
typedef struct DTEnab DTEnab;
typedef struct DTChan DTChan;
typedef struct DTExpr DTExpr;
typedef struct DTProvider DTProvider;
typedef struct DTAgg DTAgg;
typedef struct DTBuf DTBuf;
typedef struct DTTrigInfo DTTrigInfo;
/*
we assign all pairs (probe,action-group) (called an enabling or DTEnab) a unique ID called EPID.
we could also use probe IDs and action group IDs but using a single 32-bit ID for both is more flexible/efficient.
epid == -1 indicates a fault record (see below)
*/
struct DTEnab {
u32int epid;
DTActGr *gr;
DTEnab *probnext, *probprev;
DTEnab *channext;
DTProbe *prob;
};
/* probes are never freed */
struct DTProbe {
int nenable;
char *name;
DTEnab enablist;
DTProvider *prov;
void *aux; /* for the provider */
DTProbe *provnext;
};
struct DTProvider {
char *name;
/*
provide() is called when the user first uses a provider.
provide() should call dtpnew() to create probes.
*/
void (*provide)(DTProvider *);
int (*enable)(DTProbe *); /* enable the probe. return >= 0 for success and < 0 for failure */
void (*disable)(DTProbe *); /* disable the probe */
/* for the library, not the provider */
DTProbe *probes;
int provided;
};
/*
the dtracy vm is a simple RISC machine with (currently) 16 64-bit registers.
all operations are 64-bit.
instruction encoding:
31:24 opcode
23:16 a
15:8 b
7:0 c
*/
enum {
/* Rc = Ra (op) Rb */
DTE_ADD = 0x00,
DTE_SUB = 0x01,
DTE_MUL = 0x02,
DTE_SDIV = 0x03,
DTE_SMOD = 0x04,
DTE_UDIV = 0x05,
DTE_UMOD = 0x06,
DTE_AND = 0x07,
DTE_OR = 0x08,
DTE_XOR = 0x09,
DTE_XNOR = 0x0A,
DTE_LSL = 0x0B, /* logical shift left */
DTE_LSR = 0x0C, /* logical shift right */
DTE_ASR = 0x0D, /* arithmetic shift right */
DTE_SEQ = 0x10, /* set if equal */
DTE_SNE = 0x11, /* set if not equal */
DTE_SLT = 0x12, /* set if less than */
DTE_SLE = 0x13, /* set if less or equal */
/* immediate operations, const = 10 top bits of ab, sign extended and shifted left by 6 bottom bits */
DTE_LDI = 0x20, /* Rc = const */
DTE_XORI = 0x21, /* Rc = Rc ^ const */
/* if(Ra (op) Rb) PC += c; */
DTE_BEQ = 0x30,
DTE_BNE = 0x31,
DTE_BLT = 0x32,
DTE_BLE = 0x33,
DTE_LDV = 0x40, /* R[b] = Var[a] */
DTE_ZXT = 0x50, /* R[c] = lower b bits of R[a], zero extended, 0 < b <= 64 */
DTE_SXT = 0x51, /* R[c] = lower b bits of R[a], sign extended, 0 < b <= 64 */
DTE_RET = 0xF0, /* RET Ra */
};
#define DTE(op,a,b,c) ((op)<<24|(a)<<16|(b)<<8|(c))
struct DTExpr {
int n;
u32int *b;
};
/*
aggregation buffers are hashtables and use a different record format.
there are DTANUMBUCKETS 4-byte buckets at the end of the buffer.
each entry is (link,id,key,val) with a 4-byte link field for the hash chains and a 4-byte aggregation id.
the aggregation id actually contains all the data in the DTAgg struct:
4-bit type
12-bit keysize in qwords
16-bit unique id
the struct is just for kernel convenience
*/
enum {
AGGCNT,
AGGSUM,
AGGAVG,
AGGSTD,
AGGMIN,
AGGMAX,
};
struct DTAgg {
int id;
u16int keysize; /* in bytes */
u16int recsize;
uchar type;
};
/* an action is an expression, plus info about what to do with the result */
struct DTAct {
enum {
ACTTRACE, /* record the result. size is the number of bytes used. 0 <= size <= 8 */
ACTTRACESTR, /* take the result to be a pointer to a null-terminated string. store it as zero-padded char[size]. */
/*
ACTAGGKEY and ACTAGGVAL together record a value in an aggregation.
they must occur as a pair and targ must point to an already allocated aggregation buffer.
currently 0 <= size <= 8.
*/
ACTAGGKEY,
ACTAGGVAL,
ACTCANCEL, /* (must be last action) don't write anything into the main buffer. used to avoid pointless records when using aggregations. */
} type;
DTExpr *p;
int size;
DTAgg agg;
};
/* an action group is an optional predicate and a set of actions. */
struct DTActGr {
u32int id;
int ref;
DTExpr *pred; /* if non-nil and evaluates to 0, skip the actions. */
int nact;
DTAct *acts;
DTChan *chan;
int reclen; /* record size, including 12-byte header */
};
/* a clause lists probe wildcard expressions and an action group. only used during set-up. */
struct DTClause {
int nprob;
char **probs;
DTActGr *gr;
};
struct DTBuf {
int wr;
uchar data[DTBUFSZ];
};
/* a chan is the kernel representation of a client. */
struct DTChan {
enum {
DTCSTOP,
DTCGO,
DTCFAULT,
} state;
char errstr[64];
u32int epidalloc; /* lowest unused EPID */
/* we have 2 buffers per cpu, one for writing and one for reading. dtcread() swaps them if empty. */
DTBuf **wrbufs;
DTBuf **rdbufs;
/* aggregations use separate buffers */
DTBuf **aggwrbufs;
DTBuf **aggrdbufs;
/* list of enablings. */
DTEnab *enab;
};
/* this struct collects the state during the execution of a probe */
struct DTTrigInfo {
/* filled in by caller of dtptrigger */
u64int arg[10];
/* filled in by dtptrigger */
int machno;
int epid;
u64int ts;
DTChan *ch;
};
/* fault records are used to note when a probe had to be aborted (e.g. because of a page fault) */
enum {
DTFILL = 1, /* illegal address */
};
void dtinit(int);
void dtsync(void);
/* probe functions */
DTProbe *dtpnew(char *, DTProvider *, void *aux);
int dtpmatch(char *, DTProbe ***);
int dtplist(DTProbe ***);
void dtptrigger(DTProbe *, DTTrigInfo *);
/* expression functions */
int dteverify(DTExpr *);
int dtefmt(Fmt *);
#pragma varargck type "I" u32int
/* action group functions */
void dtgpack(Fmt *, DTActGr *);
char *dtgunpack(char *, DTActGr **);
int dtgverify(DTChan *, DTActGr *);
void dtgfree(DTActGr *);
/* clause functions */
void dtclpack(Fmt *, DTClause *);
char *dtclunpack(char *, DTClause **);
void dtclfree(DTClause *);
/* chan functions */
DTChan *dtcnew(void);
void dtcfree(DTChan *);
int dtcaddgr(DTChan *, char *, DTActGr *);
int dtcaddcl(DTChan *, DTClause *);
int dtcread(DTChan *, void *, int);
int dtcaggread(DTChan *, void *, int);
void dtcreset(DTChan *);
void dtcrun(DTChan *, int);
int dtcfault(DTTrigInfo *, int, char *, ...);
/* aggbuf functions */
int dtaunpackid(DTAgg *);
void dtarecord(DTChan *, int, DTAgg *, uchar *, int, s64int);
extern DTProvider *dtproviders[];
extern int dtnmach;
/* helper */
char *dtstrdup(char *);
/* these functions are provided by the kernel interface */
uvlong dttime(void); /* return current timestamp */
void *dtrealloc(void *, ulong);
void dtfree(void *);
void *dtmalloc(ulong);
int dtmachlock(int); /* lock the per-cpu lock */
void dtmachunlock(int); /* unlock the per-cpu lock */
void dtcoherence(void); /* memory barrier */
uvlong dtgetvar(int); /* return the value of a variable */
int dtpeek(uvlong, void*, int); /* safe memmemove(). returns -1 on error. */
enum {
DTV_ARG0,
DTV_ARG1,
DTV_ARG2,
DTV_ARG3,
DTV_ARG4,
DTV_ARG5,
DTV_ARG6,
DTV_ARG7,
DTV_ARG8,
DTV_ARG9,
DTV_PID,
DTV_MACHNO,
DTV_TIME,
DTV_PROBE,
DTNVARS,
};
extern char *dtvarnames[DTNVARS];