Date: Tue, 14 Nov 2006 09:01:03 +0900 From: Pyun YongHyeon <pyunyh@gmail.com> To: Pieter de Goeje <pieter@degoeje.nl> Cc: freebsd-current@freebsd.org Subject: Re: Call for re(4) TSO/VLAN testers Message-ID: <20061114000103.GA5517@cdnetworks.co.kr> In-Reply-To: <200611131637.57216.pieter@degoeje.nl> References: <20061111011051.GB5233@cdnetworks.co.kr> <200611131637.57216.pieter@degoeje.nl>
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On Mon, Nov 13, 2006 at 04:37:57PM +0100, Pieter de Goeje wrote: > On Saturday 11 November 2006 02:10, Pyun YongHyeon wrote: > > With TSO you can see reduced system load while large file transfers > > is in progress. Please test the patch and report any unusual things > > you've found. > > Idle time has increased from 0% to 25% with this patch while sustaining the > transferrate (520Mbit/s) previously reached with iperf. > With the patch the number of interrupts/sec. was halved from 32K to 16K. > > The test was performed on a fresh current without any tuning but with debug > support removed. > > System details: > CPU: AMD Sempron(tm) 2400+ (1659.95-MHz 686-class CPU) > re0@pci0:9:0: class=0x020000 card=0x816910ec chip=0x816910ec rev=0x10 > hdr=0x00 > vendor = 'Realtek Semiconductor' > device = 'RTL8169 Gigabit Ethernet Adapter' > > The receiving end was probably limiting the transferrate. > Thanks for reporting. ATM re(4) uses still small number of Tx descriptors(i.e. 64 entries) due to the hardware limitation of 8139C+. 8169 family can have up to 1024 Tx descriptors. If we want to use more Tx descriptors on 8169 the internal structure should be modified to support both 8139C+ and 8169. I guess it would require major Tx path overhaul. Because I have just plain PCI 8169 hardware I can't sure increasing number of Tx descriptors on re(4) help Tx performance of the driver. I guess 64 Tx descriptors are not sufficient to saturate giga bit link. Would please try attached patch and report the performance of patched re(4) driver? -- Regards, Pyun YongHyeon
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