linux-kernel - [PATCH 0/6] bpf: hash: optimization

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 15 Dec 2015 19:20:58 +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
Subject: [PATCH 0/6] bpf: hash: optimization

Hi,

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

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

2) kmalloc() is called in htab_map_update_elem() for allocating
element, together with one global counter for tracking how many
elementes have been allocated. kmalloc is often a bit slow,
and the global counter doesn't scale well. This patch pre-allocates
one element pool and uses percpu ida for runtime element allocation/free,
and the global counter is removed too with this approach.

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: 1332K IOPS
	- without running eBPF prog: 1492K IOPS

 include/linux/rculist.h |  55 +++++++++++
 kernel/bpf/hashtab.c    | 247 ++++++++++++++++++++++++++++++++++++++----------
 2 files changed, 252 insertions(+), 50 deletions(-)

Thanks,
Ming 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/