On Sat, 20 Feb 2021 09:50:05 GMT, Hamlin Li <[email protected]> wrote:
>> For jmap -histo we have: >> >> parallel=<number> parallel threads number for heap iteration: >> parallel=0 default behavior, use >> predefined number of threads >> parallel=1 disable parallel heap iteration >> parallel=<N> use N threads for parallel >> heap iteration >> >> It's a bit inconsistent here in that it says <number>, <N>, and N. I'd like >> to see that cleaned up at some point along with a few other things (as part >> of a separate PR). However, my point is that the value of the argument is >> given a name, <number> in this case, so it can be referenced in the help >> output. However, jmap help is done differently than jcmd help, which doesn't >> give names to the value of options. For example, GC.heap_dump has: >> >> Options: (options must be specified using the <key> or <key>=<value> syntax) >> -all : [optional] Dump all objects, including unreachable objects >> (BOOLEAN, false) >> -gz : [optional] If specified, the heap dump is written in gzipped >> format using the given compression level. 1 (recommended) is the fastest, 9 >> the strongest compression. (INT, 1) >> >> The -gz option is much like -parallel in that a value is given for it, but >> there is no "name" for that value in the help output. So maybe we should >> avoid calling it "n" or <n>, or anything like that: >> >> "Number of parallel threads to use for heap inspection." >> "0 (the default) means let the VM determine the number of threads to use. " >> "1 means use one thread (disable parallelism). " >> "For any other value the VM will try to use the specified number of threads, >> but might use fewer." >> >> I think we can leave out "Must be positive." It should be obvious, and I >> assume an error is generated if negative number is given. > > Sure, thanks for the detailed reviewing. > Let me record the help message as below: > "Number of parallel threads to use for heap inspection." > "0 (the default) means let the VM determine the number of threads to use. > " > "1 means use one thread (disable parallelism). " > "For any other value the VM will try to use the specified number of > threads, but might use fewer." "Number of parallel threads to use for heap inspection." "0 (the default) means let the VM determine the number of threads to use. " "1 means use one thread (disable parallelism). " "For any other value the VM will try to use the specified number of threads, but might use fewer." I like this approach - good idea. ------------- PR: https://git.openjdk.java.net/jdk/pull/2379
