Re: packet size vs inter-packet gap
From: jamal <hidden>
Date: 2004-11-27 22:41:21
Ah, try that on different pieces of h/ware. i.e 32/33, 64/66 and compare before and after results. You may be suprised by the oddity;-> Actually, why not use patch i supplied? cheers, jamal On Sat, 2004-11-27 at 17:06, Lennert Buytenhek wrote:
quoted hunk ↗ jump to hunk
(cc'ing netdev and e1000-devel) On Thu, Nov 25, 2004 at 11:49:45PM -0500, jamal wrote:quoted
Would be nice to see what happens when you kick the DMA only after filling up the ring.Just to 'confirm' what you've been seeing, even this tiny little patch: diff -urN e1000.orig/e1000_main.c e1000/e1000_main.c--- e1000.orig/e1000_main.c 2004-11-24 15:35:23.000000000 +0100 +++ e1000/e1000_main.c 2004-11-27 22:57:08.429782838 +0100@@ -1720,7 +1735,9 @@ wmb(); tx_ring->next_to_use = i; + if ((i % 4) == 0) { E1000_WRITE_REG(&adapter->hw, TDT, i); + } }changes my 60B TX rate numbers from: 612597pps 612447pps 612381pps 612568pps 612579pps to: 614158pps 614179pps 614186pps 614169pps 614171pps 614150pps 614180pps 614163pps 614179pps (As before, 32/66, 82541PI, SMP Xeon 2.4, 2.6.9-something.) 'tis not much but definitely makes _some_ difference. cheers, Lennert