SHMEM_SET_CACHE_INV(3)

💖 SHMEM_SET_CACHE_INV(3) — the Open MPI era, bestie 💖

okay so sit down, hydrate, because we're talking about a whole little family of cache-control girlies from Open MPI. This is the <rainbow>SHMEM_SET_CACHE_INV(3)</rainbow> page, and she brought friends:

• shmem_clear_cache_inv(3)
• shmem_set_cache_inv(3)
• shmem_set_cache_line_inv(3)
• shmem_udcflush(3)
• shmem_udcflush_line(3)

...and they're all about Controls data cache utilities. that's the whole vibe. data. cache. utilities. 💅

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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)

like, look at them all lined up. iconic. no cap. 😌

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🌸 DESCRIPTION 🌸

so the cache line control routines take this one argument, and she's the 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 Fortran? it can be of any kind 🫶

now let's meet everybody one by one, bestie:

• shmem_clear_cache_inv — disables automatic cache coherency mode that was previously enabled by shmem_set_cache_inv or shmem_set_cache_line_inv. it's the "we're done here, turn it off" button 🎀
• shmem_clear_cache_line_inv — disables automatic cache coherency mode for the cache line associated with the address of target only. just that one line. she's specific. 💅
• shmem_set_cache_inv — enables the OpenSHMEM API to automatically decide the best strategy for cache coherency. basically she hands the aux cord to the API and trusts her judgment. lowkey powerful. 🔥
• shmem_set_cache_line_inv — enables automatic cache coherency mode for the cache line associated with the address of target only. again: just that line. no overstepping. ✨
• shmem_clear_cache_inv — disables automatic cache coherency mode previously enabled by shmem_set_cache_inv or shmem_set_cache_line_inv. yes she said it twice, and yes I'm telling you twice, because the manpage said it twice and I do not skip details around here. periodt. 💀
• shmem_udcflush — makes the entire user data cache coherent. the whole thing. all of it. 😤
• shmem_udcflush_line — makes coherent the cache line that corresponds with the address specified by target. just the one line, matching the address. cute, targeted, effective. 🎯

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📝 NOTES 📝

listen, these routines have been retained for improved backward compatibility with legacy architectures. so they're the vintage pieces you keep because they still eat. 👑

See also:

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

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👑 Copyright 👑

2003-2026, The Open MPI Community

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okay so that's the whole page, bestie — every flag-shaped thing, every function, every note, all present and accounted for, nothing dropped, nothing invented. 🫶💖

and because I promised a cute sign-off: this little masterpiece is courtesy of Open MPI, and the date on her birth certificate reads Sep 10, 2026 — so go make your data cache coherent and slay the day, mwah 💅✨🌈