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
| ||
|
Date: Thu, 15 Jan 2015 22:51:30 -0500 From: Steven Rostedt <rostedt@...dmis.org> To: Christoph Lameter <cl@...ux.com> Cc: Andrew Morton <akpm@...ux-foundation.org>, Joonsoo Kim <iamjoonsoo.kim@....com>, Pekka Enberg <penberg@...nel.org>, David Rientjes <rientjes@...gle.com>, linux-mm@...ck.org, linux-kernel@...r.kernel.org, Jesper Dangaard Brouer <brouer@...hat.com>, Thomas Gleixner <tglx@...utronix.de>, Peter Zijlstra <peterz@...radead.org> Subject: Re: [PATCH v2 1/2] mm/slub: optimize alloc/free fastpath by removing preemption on/off On Thu, 15 Jan 2015 21:27:14 -0600 (CST) Christoph Lameter <cl@...ux.com> wrote: > > The %gs register is not used since the address of the per cpu area is > available as one of the first fields in the per cpu areas. Have you disassembled your code? Looking at put_cpu_partial() from 3.19-rc3 where it does: oldpage = this_cpu_read(s->cpu_slab->partial); I get: mov %gs:0x18(%rax),%rdx Looks to me that %gs is used. I haven't done benchmarks in a while, so perhaps accessing the %gs segment isn't as expensive as I saw it before. I'll have to profile function tracing on my i7 and see where things are slow again. -- Steve -- 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