linux-kernel - [PATCH v1 0/3] bpf: hash: use per-bucket spinlock

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Message-Id: <1451307326-12807-1-git-send-email-tom.leiming@gmail.com>
Date:	Mon, 28 Dec 2015 20:55:23 +0800
From:	Ming Lei <tom.leiming@...il.com>
To:	linux-kernel@...r.kernel.org, Alexei Starovoitov <ast@...nel.org>
Cc:	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	Daniel Borkmann <daniel@...earbox.net>
Subject: [PATCH v1 0/3] bpf: hash: use per-bucket spinlock

Hi,

This patchset tries to optimize ebpf hash map, and follows
the idea:

	Both htab_map_update_elem() and htab_map_delete_elem()
	can be called from eBPF program, and they may be in kernel
	hot path, it isn't efficient to use a per-hashtable lock
	in this two helpers, so this patch converts the lock into
	per-bucket spinlock.

With this patchset, looks the performance penalty from eBPF
decreased a lot, see the following test:

	1) run 'tools/biolatency' of bcc before running block test;

	2) run fio to test block throught over /dev/nullb0,
	(randread, 16jobs, libaio, 4k bs) and the test box
	is one 24cores(dual sockets) VM server:
	- without patchset:  607K IOPS
	- with this patchset: 1184K IOPS
	- without running eBPF prog: 1492K IOPS

TODO:
	- remove the per-hashtable atomic counter

V1:
	- fix the wrong 3/3 patch 


 kernel/bpf/hashtab.c | 60 +++++++++++++++++++++++++++++++---------------------
 1 file changed, 36 insertions(+), 24 deletions(-)

Thanks,

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