Dnia Czwartek, 16 Kwietnia 2015 13:30 Zhoupeng <[email protected]> napisał(a) > I'm using Rtnet with 82583 ethernet card. > It takes about 2us to send AF_PACKET using rt_dev_sendmsg(), about 200 bytes > of data. > > It is pretty fast, but I want to find what takes so long. > At last I find that "writel(tx_ring->tail)" spend above 1us to complete. > > This is just MMIO write to 82583, of course MMIO is uncache. > And PCIE ASPM is disabled, so L0s is not the problem. > > I think PCIE Memory Write TLPs is fast enough, but why spend so much time?
Hi, There is an interesting article that may be relevant to this issue "PCI Express as a Killer of Software-based Real-Time Ethernet" You can find copy in the attachment. Best Mariusz > thanks, > _______________________________________________ > Xenomai mailing list > [email protected] > http://www.xenomai.org/mailman/listinfo/xenomai -------------- next part -------------- A non-text attachment was scrubbed... Name: rteth_hw_eval.pdf Type: application/x-unknown Size: 875870 bytes Desc: not available URL: <http://www.xenomai.org/pipermail/xenomai/attachments/20150416/f9dc8e97/attachment.bin> _______________________________________________ Xenomai mailing list [email protected] http://www.xenomai.org/mailman/listinfo/xenomai
