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Re: [E1000-devel] Slower performance on E5 than i7?
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From: Fujinaka, T. <tod...@in...> - 2013-09-22 17:38:44
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Can you tell us which motherboard you're using? This is the weekend for me so I'm just giving you a quick (little-research) answer, but most recent motherboards I've seen require 3 DIMMs per CPU or performance will be impacted. Todd Fujinaka Software Application Engineer Networking Division (ND) Intel Corporation tod...@in... (503) 712-4565 -----Original Message----- From: Ben Greear [mailto:gr...@ca...] Sent: Saturday, September 21, 2013 9:03 AM To: Waskiewicz Jr, Peter P Cc: e1000-devel list Subject: Re: [E1000-devel] Slower performance on E5 than i7? On 09/20/2013 11:14 PM, Waskiewicz Jr, Peter P wrote: > On Fri, 2013-09-20 at 20:51 -0700, Ben Greear wrote: >> We have been seeing across-the-board network performance issues with >> the E5 2643 v/s an I7-980. >> We've been trying ixgbe, igb, and 'veth' virtual devices. >> >> Driven by user space or pktgen, the E5 is usually slower by a >> noticeable bit. We did disable the VTD BIOS thing that really kills >> performance, but perhaps there are other BIOS things we should tune >> in the E5 system? >> >> We tried various kernels back to about 3.0 and the general slowness >> remains. >> >> Has anyone done similar comparisons and seen issues? > > If I'm not mistaken, the E5 has a lower max frequency than the desktop > parts. What I suspect is you're seeing your workloads physically run > faster on the I7 due to turbo pushing the core past 3 GHz, but the E5 > I think hovers in the 2.5-3.0 range. The E5 claims 3.3Ghz. The i7 is a bit faster, but not that much (the slightly slower I7-975 out performs it as well). For all our testing we are running extended loads, so I'm guessing the temporary turbo boost will not have much effect on our testing. > Other factors could be how memory is populated in both systems. Are > you sure all channels are populated in both systems? Both systems have 4x4GB sticks...I *think* it is fully populated. It seems to me that the E5 is more susceptible to cache issues...for instance if everything is *just* right, the E5 can come close to pushing full tx + rx on 4 x 10G ports using pktgen, but if softirqd twiddles with things performance will degrade significantly. The same issues are seen on the i7, but it seems to a much less degree. One of our engineers found some cache thing to disable in the E5 system's BIOS that gave another 15% improvement, but I don't have the details at this time. > This is just some of the quick low-hanging fruit I can think of now. I appreciate the help. Is there a current suggested replacement for the I7 (since they seem to be mostly end-of-life)? Thanks, Ben > > Cheers, > -PJ > -- Ben Greear <gr...@ca...> Candela Technologies Inc http://www.candelatech.com ------------------------------------------------------------------------------ LIMITED TIME SALE - Full Year of Microsoft Training For Just $49.99! 1,500+ hours of tutorials including VisualStudio 2012, Windows 8, SharePoint 2013, SQL 2012, MVC 4, more. BEST VALUE: New Multi-Library Power Pack includes Mobile, Cloud, Java, and UX Design. Lowest price ever! Ends 9/22/13. http://pubads.g.doubleclick.net/gampad/clk?id=64545871&iu=/4140/ostg.clktrk _______________________________________________ E1000-devel mailing list E10...@li... https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired |
