---
name: "tapset::iosched"
section: "3stap"
platform: "linux"
package: "systemtap-doc"
version: "1.7-1+deb7u1"
release: "Debian 7 (Wheezy)"
platforms: ["linux"]
url: "https://new.carta.tech/tapset::iosched"
---

# tapset::iosched(3stap)

systemtap IO scheduler probe points

## NAME

tapset::iosched - systemtap IO scheduler probe points

## DESCRIPTION

This family of probe points is used to probe the IO scheduler  activities.  It contains the following probe points:

- **ioscheduler.elv\_next\_request**

  Fires when retrieves a request from request queue

  **Arguments:**

  *elevator\_name*\
     The elevator name

- **ioscheduler.elv\_next\_request.return**

  Fires when return from retrieving a request

  **Arguments:**

  *req*\
     Address of the request

  *req\_flags*\
     request flags

  *disk\_major*\
     disk major number of the request

  *disk\_minor*\
     disk minor number of the request

- **ioscheduler.elv\_add\_request**

  Fires when add a request into request queue

  **Arguments:**

  *elevator\_name*\
     The elevator name

  *req*\
     Address of the request

  *req\_flags*\
     request flags

  *disk\_major*\
     disk major number of the request

  *disk\_minor*\
     disk minor number of the request

- **ioscheduler.elv\_completed\_request**

  Fires when a request is completed

  **Arguments:**

  *elevator\_name*\
     The elevator name

  *req*\
     Address of the request

  *req\_flags*\
     request flags

  *disk\_major*\
     disk major number of the request

  *disk\_minor*\
     disk minor number of the request

## SEE ALSO

[*stap*(1)](/stap/1.md), [*stapprobes*(3stap)](/stapprobes/3stap.md)