Support for increasing thread cache size in TCMalloc.

Currently TCMalloc's default tc size is 32MB.
This causes poor performance in ceph storage.
A new ceph_tcmalloc_tc_bytes option has been added
with a default of 128MB.

128 MB is default TC size at above jewel version.
and if we don't set this config,
osd daemon will running with 32 MB.
because 32MB is default size in TCmalloc 2.4 version.
32MB and 128MB are twice the performance difference.
- reference : https://www.slideshare.net/Red_Hat_Storage/


ceph-performance-projects-leading-up-to-jewel-61050682

Closes-Bug: #1693692

Change-Id: I0d25c92917b11a29bcfd18f9c129cae328fa2d3e
Signed-off-by: jangseon ryu <jangseon.ryu@navercorp.com>

ansible/roles/ceph/defaults/main.yml

@@ -22,6 +22,9 @@ ceph_rgw_image_full: "{{ ceph_rgw_image }}:{{ ceph_rgw_tag }}"
 ####################
 osd_initial_weight: "1"
 
+# Increase tcmalloc cache size
+ceph_tcmalloc_tc_bytes: "134217728"
+
 ####################
 ## Ceph_rgw_keystone
 ####################

ansible/roles/ceph/tasks/start_osds.yml

@@ -37,6 +37,7 @@
       KOLLA_CONFIG_STRATEGY: "{{ config_strategy }}"
       OSD_ID: "{{ item.0.stdout }}"
       JOURNAL_PARTITION: "{{ item.1.journal }}"
+      TCMALLOC_MAX_TOTAL_THREAD_CACHE_BYTES: "{{ ceph_tcmalloc_tc_bytes }}"
     image: "{{ ceph_osd_image_full }}"
     name: "ceph_osd_{{ item.0.stdout }}"
     pid_mode: "host"