Why _TLS ptls need duplicate OSTLS's memory?

[chyin6]

Extensible-Storage-Engine/dev/ese/src/os/thread.cxx

Line 173 in 104bfce

ULONG cb_TLS = sizeof( _TLS ) + sizeof( OSTLS ) + g_cbUserTLSSize;

ostls in _TLS is a struct not a point so sizeof(_TLS) already contains sizeof(OSTLS). Why _TLS's instance ptls need duplicate OSTLS's memory? I tried to delete sizeof(OSTLS) and run the sample. Everything seems good.

[MsftBrettShirley]

What a subtle / good find. I checked in a recent re-org in how we size the TLS and fixed this as part of it ... saving ESE > 200 bytes per thread. Thanks. But just FYI - I can not be sure how long though before that change makes it out of our internal process to github.

[chyin6]

WOW. Thanks for your work @MsftBrettShirley . Such an amazing suprise! 😃 After all this time, I got a reply.