[sheepdog] [sheepdog/sheepdog] 6fa0cd: sheep: add a new option for using fixed workqueues...

[Hitoshi Mitake]

  Branch: refs/heads/wq
  Home:   https://github.com/sheepdog/sheepdog
  Commit: 6fa0cd42c6995785944d878b69b7f1afb43a14df
      https://github.com/sheepdog/sheepdog/commit/6fa0cd42c6995785944d878b69b7f1afb43a14df
  Author: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
  Date:   2016-07-25 (Mon, 25 Jul 2016)

  Changed paths:
    M sheep/sheep.c

  Log Message:
  -----------
  sheep: add a new option for using fixed workqueues for stable performance

This commit adds a new option -w to sheep for using fixed workqueues.
Example of usage:
$ sheep -w gway=100,net=300

If the option isn't passed, sheep uses unlimited queues but it is
highly dicouraged for stable and high IOPS.

Based on @luckychen 's report, the patch doubles IOPS with well
configured parameters: 40,000 -> 83,460 IOPS

Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>