MPI_T_PVAR_STOP(3)

💅 MPI_T_PVAR_STOP(3) — the Open MPI glow-up

ok so bestie, welcome to the Open MPI corner of the internet, where we do performance variables and we do them correctly. this page is about MPI_T_pvar_start and MPI_T_pvar_stop — the little duo that turns your performance variables on and off. it's giving power switch energy ⚡ and honestly? iconic.

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✨ NAME ✨

MPI_T_pvar_start, MPI_T_pvar_stop — start/stop a performance variable 🎀

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✨ SYNTAX ✨

🦋 C Syntax

#include <mpi.h>

int MPI_T_pvar_start(MPI_T_pvar_session session, MPI_T_pvar_handle handle)

int MPI_T_pvar_stop(MPI_T_pvar_session session, MPI_T_pvar_handle handle)

like yes, both functions, same shape, one starts and one stops. no cap 🫶

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✨ INPUT PARAMETERS ✨

• session — Performance experiment session. this is your lil experiment context, your whole vibe container 💜
• handle — Performance variable handle. the specific variable you're talking to, bestie 🎀

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✨ DESCRIPTION ✨

okay so MPI_T_pvar_start starts the performance variable with the handle you passed in handle. and here's the fun part — you can pass the special value MPI_T_PVAR_ALL_HANDLES as handle and it will start all the non-continuous handles in the session you gave in session. all of them. at once. slay 🔥

MPI_T_pvar_stop does the opposite — it stops the performance variable with the handle in handle. same deal: MPI_T_PVAR_ALL_HANDLES can be passed in handle to stop all the non-continuous handles in the session specified in session. clean, symmetrical, obsessed 💖

⚠️ real talk though: continuous performance variables can neither be started nor stopped. don't even try it, they're built different and they said no 💀

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✨ ERRORS ✨

MPI_T_pvar_start and MPI_T_pvar_stop() will fail if:

• MPI_T_ERR_NOT_INITIALIZED — The MPI Tools interface not initialized. bestie you gotta init first 😭
• MPI_T_ERR_INVALID_SESSION — Session parameter is not a valid session. that session is not giving what you think it's giving 🙈
• MPI_T_ERR_INVALID_HANDLE — Invalid handle or handle not associated with the session. this handle doesn't belong to that session, awkward 💀
• MPI_T_ERR_PVAR_NO_STARTSTOP — The variable cannot be started or stopped. (see: continuous variables, they said no 🚫)

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✨ SEE ALSO ✨

• MPI_T_pvar_get_info — go get the deets, iykyk 👑

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🌈 a lil sign-off 🌈

this page is from Open MPI, dated Sep 10, 2026, and the copyright belongs to 2003-2026, The Open MPI Community — full credit to the icons who wrote it 🫶✨

stay hydrated, read your man pages, and go start (and stop) some performance variables responsibly 💖🎀🦋