ollama - 💡(How to fix) Fix `ollama ls` takes 5 seconds in interactive terminal (pselect6 timeout on stdout) [1 participants]

Describe the bug

ollama ls (and other list/ps commands) consistently takes exactly 5 seconds when run in an interactive terminal (PTY). The same command completes in ~14ms when stdout is piped or not connected to a TTY.

Steps to reproduce

1. Run time ollama ls in any interactive terminal (xterm, tmux, gnome-terminal, etc.)
2. Observe ~5 second delay before output appears

Reproducible via script which creates a PTY:

# Slow (5s) - with PTY
script -qc 'time ollama ls' /dev/null

# Fast (14ms) - without PTY
time ollama ls | cat

Expected behavior

ollama ls should complete in milliseconds regardless of terminal type.

Root cause (strace analysis)

strace -f -T shows the TUI rendering framework performs a pselect6 on stdout (fd 1) with a 5-second timeout:

pselect6(2, [1], NULL, NULL, {tv_sec=5, tv_nsec=0}, NULL) = 1 (in [1])       # first call succeeds
pselect6(2, [1], NULL, NULL, {tv_sec=5, tv_nsec=0}, NULL) = 0 (Timeout) <5.005162>  # second call times out

After the 5s timeout, the process proceeds normally:

ioctl(1, TCSETS, ...)  # terminal control
SIGURG                  # Go runtime signal

The 5-second wall time is entirely I/O wait (user=7ms, sys=14ms, real=5020ms).

Workaround

Setting TERM=dumb bypasses the TUI rendering and eliminates the delay:

TERM=dumb time ollama ls  # 14ms

Alternatively, pipe output: ollama ls | cat

Environment

• OS: Ubuntu 24.04, Linux 6.8.0-107-generic
• Ollama: v0.18.2
• GPU: NVIDIA GeForce RTX 5060 Ti (driver 590.48.01, CUDA 13.1)
• Terminal: Reproduced in gnome-terminal, tmux, and via script -qc
• Shell: bash 5.2

Additional context

The issue is not related to network/proxy configuration (verified by testing with and without proxy). It is purely a terminal I/O issue in the CLI's TUI framework (likely bubbletea). The pselect6 on stdout fd behavior suggests a race condition or incorrect fd readiness check in the terminal rendering pipeline.