| 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
| ||
|
Message-ID: <538F7C7D.9040606@linux.vnet.ibm.com> Date: Thu, 05 Jun 2014 01:37:25 +0530 From: "Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com> To: Peter Zijlstra <peterz@...radead.org> CC: akpm@...ux-foundation.org, fweisbec@...il.com, tglx@...utronix.de, hch@...radead.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH] smp, ipi: Speed up IPI handling by invoking the callbacks in reverse order On 06/05/2014 01:17 AM, Peter Zijlstra wrote: > On Thu, Jun 05, 2014 at 01:09:35AM +0530, Srivatsa S. Bhat wrote: >> The current implementation of lockless list (llist) has a drawback: if we >> want to traverse the list in FIFO order (oldest to newest), we need to >> reverse the list first (and this can be expensive if the list is large, >> since this is an O(n) operation). > > Have you actually looked at the queue depth of this thing? Large queues > are a problem for interrupt latency. > Actually, I wrote this patch just by looking at the code and realizing that we don't need to reverse the list. In practice, I haven't actually seen any noticeable interrupt latencies or large queues so far. So I think this patch is just a very tiny optimization, that's all. Regards, Srivatsa S. Bhat -- 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