On Sun, Dec 10, 2017 at 5:58 PM, Peter C. Wallace <pcw@xxxxxxxxxxx> wrote: > On Sun, 10 Dec 2017, Ran Shalit wrote: > >> Date: Sun, 10 Dec 2017 17:40:27 +0200 >> From: Ran Shalit <ranshalit@xxxxxxxxx> >> To: linux-rt-users <linux-rt-users@xxxxxxxxxxxxxxx> >> Subject: Ethernet chunks behavior >> >> >> Hello, >> >> We use rt patch with UBUNTU,and have a "high priority" thread with 1 >> millisecond periodic rate. >> That rt thread, also send UDP Ethernet packets. >> This project was ported from VXWORKS project, but we notice the >> following difference: >> Although the rt thread gets its 1 millisecond periodic in high >> accuracy, the udp is being send in chunks, as if several messages are >> aggregated before being delivered. >> >> Is there any reason for such behavior ? >> >> Regards, >> Ran >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-rt-users" >> in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > > Is it possible your Ethernet driver has coalesce options enabled? > > Check with ethtool -c devname > Hi, I will check this tomorrow and update, I also see that there are other methods for reducing lateny, In the following guide chapter 12: https://access.redhat.com/sites/default/files/attachments/201501-perf-brief-low-latency-tuning-rhel7-v1.1.pdf such as irqbalance, and there is also some tunning such as sysctl -w net.ipv4.tcp_low_latency=1 Regards, Ran > > Peter Wallace > Mesa Electronics > -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
