Re: kern/57160: NFS (over TCP) very slow in 10_BETA

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

The following reply was made to PR kern/57160; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/57160: NFS (over TCP) very slow in 10_BETA
Date: Tue, 31 Jan 2023 14:57:39 +0100

 On Mon, Jan 30, 2023 at 09:48:23PM +0100, Manuel Bouyer wrote:
 > On Wed, Jan 25, 2023 at 11:35:56PM +0100, Manuel Bouyer wrote:
 > > I just noticed that if there is significant network traffic in background when
 > > reading my mailbox, nfs is back at full speed.
 > > I noticed this while I had a file download over ADSL.
 > > A single ping has noticeable effect; a ping -i0.1 gives an appreciable
 > > boost. 
 > > 
 > > Without background traffic reading a small (45 messages) mailbox takes 6 or 7
 > > seconds. With a background ping, reading the same mailbox takes half the
 > > time. With ping -i0.1 it's about 0.5s
 > > 
 > > For a large mailbox, with ping -i0.1 in background it takes about 15s.
 > > With a
 > > cat /dev/zero | ssh someremotehost "cat > /dev/null"
 > > in background, this time is down to 4 or 5s, with is the speed I had with
 > > NetBSD 9.x
 > > 
 > > Maybe the issue is related to my network adapter (like: RX interrupts are
 > > sometime missed). It's a
 > > [     1.032289] alc0 at pci2 dev 0 function 0: Atheros AR8161 PCIe Gigabit Ethernet
 > > [     1.032289] alc0: interrupting at ioapic0 pin 16
 > > [     1.032289] alc0: Ethernet address 94:de:80:21:be:c0
 > > [     1.032289] atphy0 at alc0 phy 0: Atheros AR8035 10/100/1000 PHY, rev. 9
 > > [     1.032289] atphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT-FDX, auto
 > > 
 > > This driver got some changes between -9 and -10, I have not investigated yet.
 > 
 > I reverted to the netbsd-9 driver (with 1.47 pulled up as this is required
 > to build on netbsd-10) and this didn't change the performances.
 > So I guess it's not a direct change in the driver which causes this problem.
 
 A way to work around the problem is to use udp mount.
 With udp:
 rochebonne:~> /usr/bin/time mutt -f Mail/Inbox 
         3.59 real         0.09 user         0.05 sys
 With tcp:
 rochebonne:~> /usr/bin/time mutt -f Mail/Inbox 
        37.91 real         0.08 user         0.06 sys
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --