libdb/util/systemtap/mutex.stp

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#!/usr/bin/stap
/*
* Copyright (c) 2010 Oracle and/or its affiliates. All rights reserved.
*
* mutex.stp - Display DB mutex wait times.
*
* Specify one particular process with -x <pid> or -c "<program> [<args>..]"
*
* Probes: mutex suspend and resume
* suspend(unsigned mutex, unsigned exclusive, unsigned alloc_id);
* resume(unsigned mutex, unsigned exclusive, unsigned alloc_id);
*
* mutex:
* is the integer mutex id returned by mutex_alloc()
* exclusive:
* is set to 1 except when obtaining a read-write latch with
* shared access (allocated with DB_MUTEX_SHARED), then it is 0.
* alloc_id:
* is one of dbinc/mutex.h's MTX_XXX definitions (i.e., the class)
*/
global idnames;
global suspend;
global mutexwaits;
global classwaits;
function getns()
{
t = gettimeofday_ns();
/*
* On some virtual machine monitors gettimeofday_ns() returns 0. When
* that happens approximate it as if this has a 2 Ghz processor.
*/
if (t == 0)
t = get_cycles() / 2;
return (t);
}
probe begin
{
idnames[1] = "APPLICATION";
idnames[2] = "ATOMIC_EMULATION";
idnames[3] = "DB_HANDLE";
idnames[4] = "ENV_DBLIST";
idnames[5] = "ENV_HANDLE";
idnames[6] = "ENV_REGION";
idnames[7] = "LOCK_REGION";
idnames[8] = "LOGICAL_LOCK";
idnames[9] = "LOG_FILENAME";
idnames[10] = "LOG_FLUSH";
idnames[11] = "LOG_HANDLE";
idnames[12] = "LOG_REGION";
idnames[13] = "MPOOLFILE_HANDLE";
idnames[14] = "MPOOL_BH";
idnames[15] = "MPOOL_FH";
idnames[16] = "MPOOL_FILE_BUCKET";
idnames[17] = "MPOOL_HANDLE";
idnames[18] = "MPOOL_HASH_BUCKET";
idnames[19] = "MPOOL_REGION";
idnames[20] = "MUTEX_REGION";
idnames[21] = "MUTEX_TEST";
idnames[22] = "REP_CHKPT";
idnames[23] = "REP_DATABASE";
idnames[24] = "REP_DIAG";
idnames[25] = "REP_EVENT";
idnames[26] = "REP_REGION";
idnames[27] = "REP_START";
idnames[28] = "REP_WAITER";
idnames[29] = "REPMGR";
idnames[30] = "SEQUENCE";
idnames[31] = "TWISTER";
idnames[32] = "TCL_EVENTS";
idnames[33] = "TXN_ACTIVE";
idnames[34] = "TXN_CHKPT";
idnames[35] = "TXN_COMMIT";
idnames[36] = "TXN_MVCC";
idnames[37] = "TXN_REGION";
}
probe process(@1).mark("mutex__suspend")
{
suspend[tid()] = getns();
}
/* mutex-resume(unsigned mutex, boolean exclusive, unsigned alloc_id, struct __db_mutex_t *mutexp) */
probe process(@1).mark("mutex__resume")
{
start = suspend[tid()];
class = idnames[$arg3];
if (start != 0) {
duration = getns() - start;
mutexwaits[$arg1, $arg2, class, tid()] <<< duration;
classwaits[class, $arg2] <<< duration;
suspend[tid()] = 0;
}
}
probe end
{
foreach ([mutex, excl, alloc_id, tid] in mutexwaits) {
printf("Mutex %d %s %s thread %d wait times in nanoseconds\n",
mutex, excl ? "exclusive" : "shared", alloc_id, tid);
print(@hist_log(mutexwaits[mutex, excl, alloc_id, tid]))
}
print("Aggregate mutex wait times grouped by (alloc_id, mode)\n");
foreach ([class, excl] in classwaits) {
printf("Mutex class %s %s wait times in nanoseconds\n", class,
excl ? "exclusive" : "shared");
print(@hist_log(classwaits[class, excl]));
}
}