On Sat, 20 Feb 2021 03:27:22 GMT, Chris Plummer <[email protected]> wrote:
>> Hamlin Li has updated the pull request incrementally with one additional >> commit since the last revision: >> >> improve jcmd GC.class_histogram to support parallel > > 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. @plummercj @sspitsyn Kindly reminder. Thanks. ------------- PR: https://git.openjdk.java.net/jdk/pull/2379
