RFR: 8246134: ZGC: Restructure hs_err sections

[Per Liden]

On 5/29/20 12:13 PM, Stefan Karlsson wrote:
> Hi all,
> 
> Please review this small patch to restructure and cleanup the 
> information ZGC prints to hs_err files (and jcmd VM.info).
> 
> https://cr.openjdk.java.net/~stefank/8246134/webrev.01/
> https://bugs.openjdk.java.net/browse/JDK-8246134
> 
> The patch:
> - Moves the Page Table dumping later, to make it easier to find the 
> other sections
> - Pretty print some info
> - Add barrier set print (mostly to get rid of awkward double new lines)
> - Update titles and cleanup newlines

Looks good. Some nits:

1) How about we move z_global_phase_string() to zGlobal.hpp/cpp and call 
it e.g. ZGlobalPhaseToString()?


2) I find code like this unnecessarily hard to read:

+  switch (ZGlobalPhase) {
+  case ZPhaseMark: return "Mark";
+  case ZPhaseMarkCompleted: return "MarkCompleted";
+  case ZPhaseRelocate: return "Relocate";
+  default: assert(false, "Unknown ZGlobalPhase"); return "Unknown";

How about:

switch (ZGlobalPhase) {
case ZPhaseMark:
   return "Mark";

case ZPhaseMarkCompleted:
   return "MarkCompleted";

case ZPhaseRelocate:
   return "Relocate";

default:
   assert(false, "Unknown ZGlobalPhase");
   return "Unknown";
}


3) I see it was like this before your change, but how about removing the 
extra space on all print_cr-lines, for example:

  317   st->print_cr( "ZGC Globals:");

to:

  317   st->print_cr("ZGC Globals:");

It also looks like the argument indentation here is off by one:

  320   st->print_cr( " Offset Max:        " SIZE_FORMAT "%s (" 
PTR_FORMAT ")",
  321               byte_size_in_exact_unit(ZAddressOffsetMax),
  322               exact_unit_for_byte_size(ZAddressOffsetMax),
  323               ZAddressOffsetMax);
  321               byte_size_in_exact_unit(ZAddressOffsetMax),
  322               exact_unit_for_byte_size(ZAddressOffsetMax),
  323               ZAddressOffsetMax);

cheers,
Per

> 
> Thanks,
> StefanK