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: Fri, 4 Oct 2013 10:15:54 +0100 From: jason.morgan@...illant.com To: netdev@...r.kernel.org Subject: Re: tx checksum offload in rtl8168evl disabled in driver Ubuntu 12.04.3 LTS + Kernel 3.8.13-8 64bit I've patched the driver to allow tx checksum offload for this chip and=20 found the following: MTU 9000 standard driver: 517Mbps with 2k + header frames MTU 9000 patched driver: 770Mbps with 2k + header frames 100% transfer without error (1e6 frames) 48% increase in performance combined with a massive decrease in CPU = effort=20 is not to be sniffed at. IMO tx offload should be more prevalent as the frames grow, to reduce CPU=20 load. OK, so make the default OFF if there is a silicon error (that spans=20 mulitple chips?) , but why prevent it being turned on in the driver? -=20 even if there is a kernel message that this might cause problems. From: Francois Romieu <romieu@...zoreil.com> To: <jason.morgan@...illant.com>, Cc: netdev@...r.kernel.org, hayeswang@...ltek.com Date: 04/10/2013 00:01 Subject: Re: tx checksum offload in rtl8168evl disabled in driver jason.morgan@...illant.com <jason.morgan@...illant.com> : [...] > I'm at 517Mbps and I've found that there seems to be a cpu bottleneck. Which kernel ? > I'm using 2k to 4k frames with a rtl8168evl. > I've found this message > http://www.spinics.net/lists/netdev/msg216530.html [...] > However the message thread, above indicates that this is not a problem and > can be changed to make tx-checksum offload possible. > > However we are using a newer chip to the on in the message thread. I've > tried to find other, more recent citations without success. > > So, why is it still turned off ? It has been disabled since d58d46b5d85139d18eb939aa7279c160bab70484 ("r8169: jumbo fixes"). Patch was submitted as a RFC on 2011/07/17 and Hayes was explicitely requested to comment on the jumbo part if necessary. Patch was submitted for inclusion on 2011/09/22. Tx checksumming and jumbo are mutually exclusive in Realtek's driver as well. It seems no recent gigabit chipset reliably supports it. > What will be the effect of turning it on (changing false to true, in the > driver line) for our chip ? YMMV. Hayes may elaborate. -- Ueimor -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists