Ondřej Mirtes ondrejmirtes

VM stack page churn on a fragmented heap

A call stack whose depth repeatedly oscillates across a VM stack page boundary allocates and frees a 256KB page on every oscillation (zend_vm_stack_extend() on the way down, zend_vm_stack_free_call_frame_ex()'s immediate efree() on the way back). Each of those allocations is served by zend_mm_alloc_large(), whose search for contiguous free pages degrades on a large, fragmented heap — in the worst case scanning every chunk's free-page bitmap, failing, and falling back to an mmap/munmap round-trip per oscillation.

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RelayCon 2016

I came to my first WWDC for two reasons: to experience the event first-hand and to meet my favourite blogging and podcaster heroes. I've been following the Apple community for about five years now so I finally decided it will be worth it to fly across the globe from Prague, Czech Republic to San Francisco.

I looked forward to RelayCon a lot and managed to get a ticket. It was great to meet all of the people I let talk to my ears so many hours every week!

I met Russell Ivanovic and talked to him for quite a while. I found our conversation so immersive that it almost felt like we're doing a podcast together. I also made a couple of friends who are not celebrities in this community.

I also introduced myself and talked to: David Smith, David Sparks, Daniel Jalkut, Ben Brooks, Craig Hockenberry and Federico Viticci. But I was looking forward the most to meet the hosts of my favo(u)rite podcast: ATP.

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