On Oct 19, 2015, at 3:10 AM, Prajakta <[email protected]> wrote:
> Is there a way by which we can get actual number of bytes of data allocated
> by JEMALLOC + number of bytes allocated by mmap / bro system call in jemalloc?
>
> I am looking for counters similar to mallinfo counters in jemalloc.
> Using mall info() we get information about memory allocations performed using
> malloc.
>
> I need similar counters from jemalloc:
> - hblkhd: Number of bytes in blocks currently allocated using mmap(2)
> - uordblks: Total number of bytes usd by in-use allocations
> - fordblks: Total number of bytes in free blocks.
>
>
> Out of above 3, I suspect, stats.allocated is similar to uordblks.
Unfortunately, mallinfo()'s API has some implementation detail baked in, and it
doesn't map perfectly to jemalloc. Nonetheless, jemalloc does provide similar,
more detailed stats.
hblkhd: Under typical operating conditions, jemalloc allocates *all* memory via
mmap(), so this stat isn't generally useful. That said,
http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.arenas.i.large.allocated
<http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.arenas.i.large.allocated>
and
http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.arenas.i.huge.allocated
<http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.arenas.i.huge.allocated>
may be of interest depending on your use case.
uordblks: Precisely the same as
http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.allocated
<http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.allocated>
.
fordblks: Use
http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.resident
<http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.resident>
or
http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.mapped
<http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.mapped>
and subtract out
http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.active
<http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html#stats.active>
.
Jason
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