explain why CPU affinity is a good idea

This commit is contained in:
Matthew Hodgson 2017-08-15 18:27:42 +01:00
parent 963015005e
commit 92168cbbc5
1 changed files with 8 additions and 0 deletions

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@ -153,10 +153,18 @@ class ServerConfig(Config):
# bit corresponding to the first logical CPU and the highest order bit
# corresponding to the last logical CPU. Not all CPUs may exist on a
# given system but a mask may specify more CPUs than are present.
#
# For example:
# 0x00000001 is processor #0,
# 0x00000003 is processors #0 and #1,
# 0xFFFFFFFF is all processors (#0 through #31).
#
# This is desirable for Synapse processes (especially workers), which are
# inherently single-threaded due to the GIL and can suffer a 30-40% slowdown
# due to cache blow-out and thread context switching if the scheduler happens
# to schedule the underlying threads across different cores.
# See https://www.mirantis.com/blog/improve-performance-python-programs-restricting-single-cpu/
#
# cpu_affinity: 0xFFFFFFFF
# Whether to serve a web client from the HTTP/HTTPS root resource.