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 for Android: free password hash cracker in your pocket
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-Id: <1430429035-25563-1-git-send-email-riel@redhat.com>
Date:	Thu, 30 Apr 2015 17:23:52 -0400
From:	riel@...hat.com
To:	linux-kernel@...r.kernel.org
Cc:	x86@...nel.org, williams@...hat.com, luto@...nel.org,
	mingo@...nel.org, bonzini@...hat.com, fweisbec@...hat.com,
	peterz@...radead.org, heiko.carstens@...ibm.com, tglx@...utronix.de
Subject: [PATCH 0/3] reduce nohz_full syscall overhead by 10%

Profiling reveals that a lot of the overhead from the nohz_full
accounting seems to come not from the accounting itself, but from
disabling and re-enabling interrupts.

This patch series removes the interrupt disabling & re-enabling
from __acct_update_integrals, which is called on both syscall
entry and exit, as well as from the user_exit called on syscall
entry.

Together they speed up a benchmark that calls getpriority in
a row 10 million times by about 10%:

		run time	system time
vanilla		5.49s		2.08s
__acct patch	5.21s		1.92s
both patches	4.88s		1.71s

--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ