The cache alignment happens because it hits a specific size threshold, and jemalloc/phkmalloc(I think!) just round everything up to be page size aligned.
The underlying problem may actually be a code change to how the math is done. It just runs slower on page-aligned alignments.. adrian On 22 September 2013 05:10, Eduardo Morras <[email protected]> wrote: > On Sat, 21 Sep 2013 12:53:36 -0700 > Adrian Chadd <[email protected]> wrote: > > > .. just as a data point - there was a thread a while ago about numeric > > processing performance on linux vs bsd. > > > > It all boiled down to how jemalloc versus the linux allocator(s) allocate > > blocks. jemalloc will page align things after a certain size. Linux > didn't. > > So when doing numeric processing, there was a lot of cache aliasing going > > on leading to inefficient cache usage and redundant memory operations. > > > > When the same workload on Linux was run on FreeBSD but with the Linux > > library/allocators, the performance was identical. > > > > No-one followed through. I think I may have to write a blog post about > it. > > There's no MALLOC_OPTIONS flag to set/unset this, but adding a new flag to > disable a feature is easier (or should be) than implementing new one. The > only problem I see to this is if the cache align happens at sbrk/mmap level. > > > > > > -adrian > > _______________________________________________ > > [email protected] mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > > To unsubscribe, send any mail to " > [email protected]" > > > --- --- > Eduardo Morras <[email protected]> > _______________________________________________ > [email protected] mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " > [email protected]" > _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[email protected]"
