RFR [XS]: 8244196: adjust output in os_linux

[David Holmes]

On 4/05/2020 8:55 pm, Baesken, Matthias wrote:
> Hi David ,  the newlines were removed by me because when looking at the hs_err files it seemed to me, that we have too much of them.
> ( but of course this might be a matter of taste , and not so much of correctness )

Very much a matter of taste. :) Presently we print:

header1:
value1
<blank>
<blank>
header2:
value2
<blank>
<blank>

whereas you are now putting all that on one line and deleting empty lines:

header1:value1
header2:value2

While I personally prefer things on one line and no blank lines I am 
concerned that this make unnecessarily break scripts that try to mine 
hs_err logs.

Also you need as space after the : so this

static void _print_ascii_file_h(const char* header, const char* 
filename, outputStream* st) {
   st->print("%s", header);

should use "%s " (and arguably the : should be part of the format string 
rather than in the header itself).

> The output part looks like (from one of our Linux x86_64 machines)  this now :
> 
> /sys/kernel/mm/transparent_hugepage/enabled:[always] madvise never
> /sys/kernel/mm/transparent_hugepage/defrag (defrag/compaction efforts parameter):[always] madvise never
> 
> /proc/sys/kernel/threads-max (system-wide limit on the number of threads):1032335
> /proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):2147483647
> /proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):81920

Please add before/after examples t the bug report.

Thanks,
David

> Best regards, Matthias
> 
> -----Original Message-----
> From: David Holmes <david.holmes at oracle.com>
> Sent: Freitag, 1. Mai 2020 01:31
> To: Baesken, Matthias <matthias.baesken at sap.com>; 'hotspot-dev at openjdk.java.net' <hotspot-dev at openjdk.java.net>
> Subject: Re: RFR [XS]: 8244196: adjust output in os_linux
> 
> Hi Matthias,
> 
> On 1/05/2020 1:46 am, Baesken, Matthias wrote:
>> Hello, please review this small change to os_linux.cpp  .
>>
>> It  uses the  recently introduced    _print_ascii_file_h
>> Function t more places (makes the code  a bit  shorter ) .
> 
> I like the intent here but I think we have lost a few newlines in the
> process. It isn't even clear to me that the result of print_ascii_file
> will end with a newline being printed. Can you check the before and
> after layout for readability please (and add to bug report).
> 
> Thanks,
> David
> 
>>
>> Bug/webrev :
>>
>> https://bugs.openjdk.java.net/browse/JDK-8244196
>>
>> http://cr.openjdk.java.net/~mbaesken/webrevs/8244196.0/
>>
>> Thanks, Matthias
>>