polling(4) says that supported devices include em(4) and that polling support is turned on and off with ifconfig's 'polling' option. But ifconfig doesn't seem to recognize that option either as a standalone request or with the initial em0 setup at boot. This is after a source cvsup (releng=6 for the frozen for 6.2 sources) yesterday and buildworld + buildkernel. em support is compiled in the kernel rather than loaded. Mobo is a Supermicro P4SCT-0 with Intel 875 chipset. Is this a known issue that I haven't found references to, or perhaps something related to my specific configuration? FreeBSD v2.netoldies.com 6.2-PRERELEASE FreeBSD 6.2-PRERELEASE #0: Fri Sep 15 15:14:07 PDT 2006 root@v2.netoldies.com:/usr/obj/usr/src/sys/V2KERNEL i386 Thanks --Bill
On 9/17/06, Bill Blue <bblue@netoldies.com> wrote:> polling(4) says that supported devices include em(4) and that polling support is turned on and off with ifconfig's 'polling' option. But ifconfig doesn't seem to recognize that option either as a standalone request or with the initial em0 setup at boot. > > This is after a source cvsup (releng=6 for the frozen for 6.2 sources) yesterday and buildworld + buildkernel. em support is compiled in the kernel rather than loaded. Mobo is a Supermicro P4SCT-0 with Intel 875 chipset. > > Is this a known issue that I haven't found references to, or perhaps something related to my specific configuration?You need polling support in the kernel, you can look at NOTES for POLLING option. Cheers, Jiawei Ye -- "If it looks like a duck, walks like a duck, and quacks like a duck, then to the end user it's a duck, and end users have made it pretty clear they want a duck; whether the duck drinks hot chocolate or coffee is irrelevant."
Bill Blue wrote:>polling(4) says that supported devices include em(4) and that polling support is turned on and off with ifconfig's 'polling' option. But ifconfig doesn't seem to recognize that option either as a standalone request or with the initial em0 setup at boot. > >This is after a source cvsup (releng=6 for the frozen for 6.2 sources) yesterday and buildworld + buildkernel. em support is compiled in the kernel rather than loaded. Mobo is a Supermicro P4SCT-0 with Intel 875 chipset. > >Is this a known issue that I haven't found references to, or perhaps something related to my specific configuration? > >FreeBSD v2.netoldies.com 6.2-PRERELEASE FreeBSD 6.2-PRERELEASE #0: Fri Sep 15 15:14:07 PDT 2006 root@v2.netoldies.com:/usr/obj/usr/src/sys/V2KERNEL i386 > >Thanks > >--Bill > > >Since 6.1 I have stopped using polling as a regular kernel seems to give good performance as compared to polling mode. In fact I used to get anything between 55-75megs/sec on 6.1 with regular cables but since upgraded to cat6 quality Ethernet cable I get practically full gigabit speed with no polling. Close to 97megs/sec is the performance I get out of my Dells with the em driver, and apparently the new em driver in 6-stable 6.2 is even faster. em(4) Dell to em(4) Dell dell1# cat /dev/zero | dd bs=1m | nc dell2 3000 ^C0+18456 records in 0+18455 records out 1209466880 bytes transferred in 12.459299 secs (97,073,429 bytes/sec) Mike
> > Since 6.1 I have stopped using polling as a regular kernel seems to give > good performance as compared to polling mode. > In fact I used to get anything between 55-75megs/sec on 6.1 with regular > cables but since upgraded to cat6 quality Ethernet cable I get > practically full gigabit speed with no polling. > Close to 97megs/sec is the performance I get out of my Dells with the em > driver, and apparently the new em driver in 6-stable 6.2 is even faster. > > em(4) Dell to em(4) Dell > dell1# cat /dev/zero | dd bs=1m | nc dell2 3000 > ^C0+18456 records in > 0+18455 records out > 1209466880 bytes transferred in 12.459299 secs (97,073,429 bytes/sec)Do you meen that from 6.2 I dont need polling for fastest performance?
On Sun, 17 Sep 2006, Eugene Kazarinov wrote:>> Since 6.1 I have stopped using polling as a regular kernel seems to give >> good performance as compared to polling mode. In fact I used to get >> anything between 55-75megs/sec on 6.1 with regular cables but since >> upgraded to cat6 quality Ethernet cable I get practically full gigabit >> speed with no polling. Close to 97megs/sec is the performance I get out of >> my Dells with the em driver, and apparently the new em driver in 6-stable >> 6.2 is even faster. >> >> em(4) Dell to em(4) Dell >> dell1# cat /dev/zero | dd bs=1m | nc dell2 3000 >> ^C0+18456 records in >> 0+18455 records out >> 1209466880 bytes transferred in 12.459299 secs (97,073,429 bytes/sec) > > Do you meen that from 6.2 I dont need polling for fastest performance?There are two benefits to polling: - Moderating interrupt rates - Scheduling control over the amount of CPU dedicated to network tasks Modern gigabit cards have interrupt moderation, so in practice you get a polling-like effect with regard to interrupt rates. With significant performance improvements in the if_em driver over the last year, it could well be that the benefits of the scheduling control no longer provide much help. Gigabit network cards also require a very high polling rate in order to be effective, since the on-card buffers quickly fill -- as a result, unless the poll rate (driven by HZ) is set extremely high, polling may actually significant reduce performance by dramatically increasing packet loss under load. Robert N M Watson Computer Laboratory University of Cambridge