Re: NetBSD 5.1 TCP performance issue (lots of ACK)

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sat, Oct 22, 2011 at 03:21:34PM +0100, Matthias Scheler wrote:
> On Mon, Oct 17, 2011 at 06:03:18PM +0200, Manuel Bouyer wrote:
> > I've been playing with glusterfs a bit today, and found some performance
> > differences between NetBSD and linux, which I tracked down to our TCP
> > stack. Basically, between a NetBSD/linux pair, performances are much
> > better than between 2 NetBSD hosts.
> 
> What kind of network interfaces have these machines?

wm0 at pci4 dev 0 function 0: i80003 dual 1000baseT Ethernet, rev. 1
wm0: interrupting at ioapic0 pin 18
wm0: PCI-Express bus
wm0: 65536 word (16 address bits) SPI EEPROM
wm0: Ethernet address 00:30:48:32:13:10
ikphy0 at wm0 phy 1: i82563 10/100/1000 media interface, rev. 2

> And are you really
> using NetBSD 5.1 or NetBSD 5.1_STABLE?

NetBSD 5.1_STABLE/amd64
        Build date   Wed Oct  5 16:51:41 UTC 2011
        Built by   builds%b6.netbsd.org@localhost

        BUILDID = '201110051530Z'
        DESTDIR = '/home/builds/ab/netbsd-5/amd64/201110051530Z-dest'

> Have you enable hardware
> checksums under NetBSD? Linux turns them on by default.

Yes, without hardware checksums and tso4 performances are much worse.

Note that both NetBSD host have good performances against the linux host.
The priblem is between the 2 NetBSD hosts. the 3 boxes have strictly
identical hardware.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--