SHMEM_CLEAR_CACHE_INV(3)

💖 SHMEM_CLEAR_CACHE_INV 💖

okay bestie, welcome to the cache coherency corner of the Open MPI manual, aka SHMEM_CLEAR_CACHE_INV(3). this page is a whole little friend group of routines and they all hang out together. let me introduce you 🫶

the squad is: shmem_clear_cache_inv(3), shmem_set_cache_inv(3), shmem_set_cache_line_inv(3), shmem_udcflush(3), and shmem_udcflush_line(3). (and also shmem_clear_cache_line_inv, who shows up later, we love her 💅)

together? they control data cache utilities. that's the whole vibe. periodt.

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✨ SYNOPSIS ✨

🎀 C or C++

#include <mpp/shmem.h>

void shmem_clear_cache_inv(void)
void shmem_clear_cache_line_inv(void *target)
void shmem_set_cache_inv(void)
void shmem_set_cache_line_inv(void *target)
void shmem_udcflush(void)
void shmem_udcflush_line(void *target)

🎀 Fortran

INCLUDE "mpp/shmem.fh"

CALL SHMEM_CLEAR_CACHE_INV
CALL SHMEM_CLEAR_CACHE_LINE_INV(target)
CALL SHMEM_SET_CACHE_INV
CALL SHMEM_SET_CACHE_LINE_INV(target)

CALL SHMEM_UDCFLUSH
CALL SHMEM_UDCFLUSH_LINE(target)

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🌸 DESCRIPTION 🌸

so there's exactly one argument that gets passed to the cache line control routines, and she's a main character:

• target — a data object that is local to the processing element (PE). target can be of any noncharacter type. and if you're doing the Fortran thing? it can be of any kind 🦋

okay now the individual glow-ups, one by one:

• shmem_clear_cache_inv — turns OFF automatic cache coherency mode that was previously enabled by shmem_set_cache_inv or shmem_set_cache_line_inv. it's the off switch bestie 🔻
• shmem_clear_cache_line_inv — turns OFF automatic cache coherency mode only for the cache line associated with the address of target. just that one line. not the whole party 🙈
• shmem_set_cache_inv — enables the OpenSHMEM API to automatically decide the best strategy for cache coherency. it's giving delegating to the algorithm, and honestly? she's right 💅
• shmem_set_cache_line_inv — enables automatic cache coherency mode only for the cache line associated with the address of target. again: one line only 🌈
• shmem_clear_cache_inv — yeah okay so this one is listed a second time, and the original says the exact same thing twice, so I'm saying it twice too, no cap: it disables automatic cache coherency mode previously enabled by shmem_set_cache_inv or shmem_set_cache_line_inv. iconic repetition behavior 👑
• shmem_udcflush — makes the entire user data cache coherent. the whole thing. full send 🔥
• shmem_udcflush_line — makes coherent the cache line that corresponds with the address specified by target. just the one line, matching the address 🎯

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⭐ NOTES ⭐

these routines have been retained for improved backward compatibility with legacy architectures. so like, they're the vintage pieces in the closet that still absolutely serve 💜

See also:

intro_shmem(3) shmem_put(3) shmem_swap(3)

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and that's the page bestie 💖 copyright 2003-2026, The Open MPI Community — and this whole cutie dropped on Sep 10, 2026, filed under SHMEM_CLEAR_CACHE_INV(3) from the Open MPI fam. mwah, go flush something coherently 🫶✨