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: Sat, 15 May 2010 13:57:08 +0200 From: Mike Galbraith <efault@....de> To: Peter Zijlstra <a.p.zijlstra@...llo.nl> Cc: Ingo Molnar <mingo@...e.hu>, LKML <linux-kernel@...r.kernel.org> Subject: commit e9e9250b: sync wakeup bustage when waker is an RT task Hi Peter, This commit excluded RT tasks from rq->load, was that intentional? The comment in struct rq states that load reflects *all* tasks, but since this commit, that's no longer true. Looking at lmbench lat_udp in a PREEMPT_RT kernel, I noticed that wake_affine() is failing for sync wakeups when it should not. It's doing so because the waker in this case is an RT kernel thread (sirq-net-rx) - we subtract the sync waker's weight, when it was never added in the first place, resulting in this_load going gaga. End result is quite high latency numbers due to tasks jabbering cross-cache. If the exclusion was intentional, I suppose I can do a waker class check in wake_affine() to fix it. -Mike -- 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