MPI_T_PVAR_STOP(3)

💅 MPI_T_PVAR_STOP(3) — the Open MPI manual, but make it cute

okay bestie, welcome to the Open MPI glow-up of MPI_T_pvar_start / MPI_T_pvar_stop ✨ this is the page that tells you how to start and stop a performance variable. yes, that's literally the whole vibe. let's get into it 🫶

---

🌸 NAME 🌸

MPI_T_pvar_start, MPI_T_pvar_stop — start/stop a performance variable, no cap 🎀

---

✨ 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, just look at those signatures. so clean. so iconic. 💅

---

🦋 INPUT PARAMETERS 🦋

• session — the performance experiment session, i.e. the group chat your variable lives in 💬
• handle — the performance variable handle, i.e. the @ of the variable you're talking to

---

🌈 DESCRIPTION 🌈

okay so MPI_T_pvar_start starts the performance variable that matches the handle you passed in. and here's the fun part — you can pass the special value MPI_T_PVAR_ALL_HANDLES in handle and it'll start all the non-continuous handles in the session you specified. batch starting, main character energy, obsessed 🔥

MPI_T_pvar_stop stops the performance variable with the handle you specified. and same deal — you can pass the special value MPI_T_PVAR_ALL_HANDLES in handle to stop all the non-continuous handles in the session you specified. so efficient. so demure. 🎀

⚠️ real talk though: continuous performance variables can neither be started nor stopped. it's not a skill issue, it's just not a thing. they do their own thing. respect it 💀

---

🔥 ERRORS 🔥

MPI_T_pvar_start and MPI_T_pvar_stop() will fail if any of these little gremlins show up:

• MPI_T_ERR_NOT_INITIALIZED — the MPI Tools interface isn't initialized 🙈 like bestie, you gotta init first
• MPI_T_ERR_INVALID_SESSION — the session parameter is not a valid session 😭 that's not a real session, that's a stranger
• MPI_T_ERR_INVALID_HANDLE — invalid handle, or a handle that's not associated with the session 💀 mismatched, awkward, we've all been there
• MPI_T_ERR_PVAR_NO_STARTSTOP — the variable cannot be started or stopped 🫠 it's giving "continuous variable, read the DESCRIPTION section"

---

👑 SEE ALSO 👑

• MPI_T_pvar_get_info — go get the info, iykyk ⭐

---

💜 COPYRIGHT 💜

2003-2026, The Open MPI Community 🌸

---

k that's the whole page bestie, you're officially an expert on starting and stopping performance variables 💖✨👑

~ with love, from the Open MPI gang, dated Sep 11, 2026 (yes the footer said that, I would never lie to you) 🎀