svn commit: r204155 - head/sys/dev/re

[Pyun YongHyeon]

Author: yongari
Date: Sun Feb 21 00:00:55 2010
New Revision: 204155
URL: http://svn.freebsd.org/changeset/base/204155

Log:
  Increase PCIe maximuim read request size to 2048. Because re(4) uses
  Tx DMA burst size 2048, I beleive PCIe maximum read request size
  also should match to the value of Tx DMA burst size. With this
  change I can get more than 800Mbps for TCP bulk transfers.
  Previously I was not able to get more than 700Mbps. If I enable TSO
  it now shows 927Mbps.

Modified:
  head/sys/dev/re/if_re.c

Modified: head/sys/dev/re/if_re.c
==============================================================================
--- head/sys/dev/re/if_re.c     Sat Feb 20 23:48:04 2010        (r204154)
+++ head/sys/dev/re/if_re.c     Sun Feb 21 00:00:55 2010        (r204155)
@@ -1162,6 +1162,9 @@ re_attach(device_t dev)
        msic = 0;
        if (pci_find_extcap(dev, PCIY_EXPRESS, &reg) == 0) {
                sc->rl_flags |= RL_FLAG_PCIE;
+               /* Set PCIe maximum read request size to 2048. */
+               if (pci_get_max_read_req(dev) < 2048)
+                       pci_set_max_read_req(dev, 2048);
                msic = pci_msi_count(dev);
                if (bootverbose)
                        device_printf(dev, "MSI count : %d\n", msic);
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