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8049717: expose L1_data_cache_line_size for diagnostic/sanity checks

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Add support for VM_Version::L1_data_cache_line_size().

Reviewed-by: dsimms, kvn, dholmes
This commit is contained in:
Daniel D. Daugherty 2014-07-15 07:33:49 -07:00
parent a36ef5533f
commit a06d36cada
10 changed files with 194 additions and 17 deletions
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64
hotspot/src/share/vm/runtime/objectMonitor.cpp
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@ -2497,6 +2497,10 @@ void ObjectMonitor::DeferredInitialize() {
SETKNOB(FastHSSEC);
#undef SETKNOB
if (Knob_Verbose) {
sanity_checks();
}
if (os::is_MP()) {
BackOffMask = (1 << Knob_SpinBackOff) - 1;
if (Knob_ReportSettings) ::printf("BackOffMask=%X\n", BackOffMask);
@ -2517,6 +2521,66 @@ void ObjectMonitor::DeferredInitialize() {
InitDone = 1;
}
void ObjectMonitor::sanity_checks() {
int error_cnt = 0;
int warning_cnt = 0;
bool verbose = Knob_Verbose != 0 NOT_PRODUCT(|| VerboseInternalVMTests);
if (verbose) {
tty->print_cr("INFO: sizeof(ObjectMonitor)=" SIZE_FORMAT,
sizeof(ObjectMonitor));
}
uint cache_line_size = VM_Version::L1_data_cache_line_size();
if (verbose) {
tty->print_cr("INFO: L1_data_cache_line_size=%u", cache_line_size);
}
ObjectMonitor dummy;
u_char *addr_begin = (u_char*)&dummy;
u_char *addr_header = (u_char*)&dummy._header;
u_char *addr_owner = (u_char*)&dummy._owner;
uint offset_header = (uint)(addr_header - addr_begin);
if (verbose) tty->print_cr("INFO: offset(_header)=%u", offset_header);
uint offset_owner = (uint)(addr_owner - addr_begin);
if (verbose) tty->print_cr("INFO: offset(_owner)=%u", offset_owner);
if ((uint)(addr_header - addr_begin) != 0) {
tty->print_cr("ERROR: offset(_header) must be zero (0).");
error_cnt++;
}
if (cache_line_size != 0) {
// We were able to determine the L1 data cache line size so
// do some cache line specific sanity checks
if ((offset_owner - offset_header) < cache_line_size) {
tty->print_cr("WARNING: the _header and _owner fields are closer "
"than a cache line which permits false sharing.");
warning_cnt++;
}
if ((sizeof(ObjectMonitor) % cache_line_size) != 0) {
tty->print_cr("WARNING: ObjectMonitor size is not a multiple of "
"a cache line which permits false sharing.");
warning_cnt++;
}
}
ObjectSynchronizer::sanity_checks(verbose, cache_line_size, &error_cnt,
&warning_cnt);
if (verbose || error_cnt != 0 || warning_cnt != 0) {
tty->print_cr("INFO: error_cnt=%d", error_cnt);
tty->print_cr("INFO: warning_cnt=%d", warning_cnt);
}
guarantee(error_cnt == 0,
"Fatal error(s) found in ObjectMonitor::sanity_checks()");
}
#ifndef PRODUCT
void ObjectMonitor::verify() {
}