poh: fix pacing, replace fd_log_wallclock

[jherrera-jump]

No description provided.

[Copilot]

Pull request overview

This PR updates the PoH tile’s timing/pacing approach by switching from direct fd_log_wallclock() reads to a calibrated fd_clock_t, and hooks clock recalibration into the stem housekeeping path to keep the clock estimate fresh without putting wallclock reads on the critical path.

Changes:

• Add an fd_clock_t instance and backing shared-memory region to fd_poh_t, plus a cached recal_next timestamp.
• Initialize the clock in fd_poh_tile and recalibrate it during stem housekeeping.
• Replace fd_log_wallclock() usage in fd_poh_advance() with fd_clock_now().

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/discof/poh/fd_poh_tile.c	Initializes fd_clock_t for PoH and adds a stem housekeeping callback to periodically recalibrate.
src/discof/poh/fd_poh.h	Extends fd_poh_t with clock state (fd_clock_t, clock_mem, recal_next) and adds a new timestamp field.
src/discof/poh/fd_poh.c	Uses fd_clock_now() for pacing calculations and records a leader begin timestamp.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.