[lttng-docs.git] / contents / understanding-lttng / core-concepts / channel / channel-buffering-schemes.md

---
id: channel-buffering-schemes
---

In the user space tracing domain, two **buffering schemes** are
available when creating a channel:

  * **Per-PID buffering**: keep one ring buffer per process.
  * **Per-UID buffering**: keep one ring buffer for all processes of
    a single user.

The per-PID buffering scheme consumes more memory than the per-UID
option if more than one process is instrumented for LTTng-UST. However,
per-PID buffering ensures that one process having a high event
throughput won't fill all the shared sub-buffers, only its own.

The Linux kernel tracing domain only has one available buffering scheme
which is to use a single ring buffer for the whole system.
Commit	Line	Data
5e0cbfb0 PP	1	---
	2	id: channel-buffering-schemes
	3	---
	4
	5	In the user space tracing domain, two buffering schemes are
	6	available when creating a channel:
	7
	8	* Per-PID buffering: keep one ring buffer per process.
	9	* Per-UID buffering: keep one ring buffer for all processes of
	10	a single user.
	11
47bfcb75	12	The per-PID buffering scheme consumes more memory than the per-UID
5e0cbfb0 PP	13	option if more than one process is instrumented for LTTng-UST. However,
	14	per-PID buffering ensures that one process having a high event
	15	throughput won't fill all the shared sub-buffers, only its own.
	16
	17	The Linux kernel tracing domain only has one available buffering scheme
	18	which is to use a single ring buffer for the whole system.