[ewg] Not seeing any SDP performance changes in OFED 1.3 beta, and I get Oops when enabling sdp_zcopy_thresh

Jim Mott jimmott at austin.rr.com
Fri Nov 30 12:03:50 PST 2007


Hi,
  This kernel Oops is new and I will look at it.  Dotan and the Mellanox regression tests have been keeping me busy recently.  There
was a problem like this, but only in multi-threaded apps using a single socket or when doing cleanup after ^C.

  I will re-enable default bzcopy behavior once all the important Mellanox regression tests are passing.  Until then, setting the
sdp_zcopy_threah variable by hand (8192 and up should give better performance) and running simple tests like netperf should be
working fine.  You should not be seeing any problem here.  [I have only tested locally with x86_64 rhat4u4, rhat5, 2.6.23.8, and
2.6.24-rc2.  Mellanox regression tests everything and they have not submitted this Oops yet.]

  I have opened bugs in the openfabrics bugzilla for everything I am currently working on.  It is down right now or I would add
pointers.


Here is my work list; additions or priority changes welcome:

SDP OPEN ISSUES LIST (Priority order)
=====================================
1) DONE: BUG: Unload of mlx4 and ib_sdp fails while SDP active
  11/6 [PATCH 1/1 V2] SDP - Fix reference count bug ...

2) DONE: BUG: Many data corruption failures
  11/11 [PATCH 1/1] SDP - Fix bug where zcopy bcopy returns ...

3) DONE: Bug 793 - kernel BUG at net/core/skbuff.c:95!
  11/26 [PATCH 1/1] SDP - bug793; skbuff changes ...

4) TODO: BUG: kernel oops in SDP regression 
  Replicated problem by hitting ^C during a transfer.  I have 
created a patch that fixes the problem, but it needs more work
to move into production.  There are some side effects I do not
yet understand.
  This is the one I am working on now.  I hope to drop it soon.
There is a bug open tracking it.

5) TODO: BUG: libsdp returns good RC when it should fail

6) TODO: BUG: aio_test fails in SDP regression

7) TODO: Bug 779 - Lock ordering problem during accept on 1.2.5
  After building a 2.6.23.8 kernel with lock checking enabled, I
can not reproduce this problem.  Looks like I'll need more input
from the reporter.  (Bug updated to say this).  I will continue to
code review though.

8) DONE: Bug 294 - connect does not allow AF_INET_SDP
  [fix in bugzilla dropped] 

9) DONE: Backport work needed to support 2.6.24

10) TODO: Package user space libsdp for Redhat
  This is supposed to be easy to do, but it will take me some time
to figure out the detail.  

11) DONE: BUG: Memory leak
  11/20 [PATCH 1/1 v2] SDP - Fix a memory leak in bzcopy
-----Original Message-----
From: ewg-bounces at lists.openfabrics.org [mailto:ewg-bounces at lists.openfabrics.org] On Behalf Of Scott Weitzenkamp (sweitzen)
Sent: Friday, November 30, 2007 12:37 PM
To: Jim Mott; Scott Weitzenkamp (sweitzen); ewg at lists.openfabrics.org
Cc: general at lists.openfabrics.org
Subject: [ewg] Not seeing any SDP performance changes in OFED 1.3 beta, and I get Oops when enabling sdp_zcopy_thresh

Jim,

Using netperf with TCP_STREAM and TCP_RR, I'm not seeing any changes in
SDP throughput or CPU utilization comparing OFED 1.3 beta and OFED
1.2.5.  Looks like I need to set a non-zero value in
/sys/module/ib_sdp/sdp_zcopy_thresh?  Do you plan to enable this by
default soon?

I tried "echo 4096 > /sys/module/ib_sdp/sdp_zcopy_thresh" on RHEL4 and
then tried netperf, and got an Oops.

Unable to handle kernel NULL pointer deref
erence at 0000000000000000 RIP:
<Nov/30 10:33 am><ffffffff80163ff0>{put_page+0}
<Nov/30 10:33 am>PML4 1a3047067 PGD 1a7a6d067 PMD 0
<Nov/30 10:33 am>Oops: 0000 [1] SMP
<Nov/30 10:33 am>CPU 0
<Nov/30 10:33 am>Modules linked in: parport_pc lp parport autofs4
i2c_dev i2c_co
re nfs lockd nfs_acl sunrpc rdma_ucm(U) rds(U) ib_sdp(U) rdma_cm(U)
iw_cm(U) ib_
addr(U) mlx4_ib(U) mlx4_core(U) ds yenta_socket pcmcia_core dm_mirror
dm_multipa
th dm_mod joydev button battery ac uhci_hcd ehci_hcd shpchp ib_mthca(U)
ib_ipoib
(U) ib_umad(U) ib_ucm(U) ib_uverbs(U) ib_cm(U) ib_sa(U) ib_mad(U)
ib_core(U) md5
 ipv6 e1000 floppy ata_piix libata sg ext3 jbd mptscsih mptsas mptspi
mptscsi mp
tbase sd_mod scsi_mod
<Nov/30 10:33 am>Pid: 6802, comm: netperf241 Not tainted
2.6.9-55.ELlargesmp
<Nov/30 10:33 am>RIP: 0010:[<ffffffff80163ff0>]
<ffffffff80163ff0>{put_page+0}
<Nov/30 10:33 am>RSP: 0018:00000101a7bcbbc0  EFLAGS: 00010203
<Nov/30 10:33 am>RAX: 0000000000000000 RBX: 0000000000000001 RCX:
00000000000002
02
<Nov/30 10:33 am>RDX: 00000101b0b43e80 RSI: 0000000000000202 RDI:
00000000000000
00
<Nov/30 10:33 am>RBP: 00000101b85761c0 R08: 0000000000000000 R09:
00000000000000
00
<Nov/30 10:33 am>R10: 0000000000000246 R11: ffffffffa02e0e36 R12:
00000101a4b330
80
<Nov/30 10:33 am>R13: 00000101a7bcbd58 R14: 0000000000000000 R15:
00000000000100
00
<Nov/30 10:33 am>FS:  0000002a95696940(0000) GS:ffffffff80500380(0000)
knlGS:000
0000000000000
<Nov/30 10:33 am>CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
<Nov/30 10:33 am>CR2: 0000000000000000 CR3: 0000000000101000 CR4:
00000000000006
e0
<Nov/30 10:33 am>Process netperf241 (pid: 6802, threadinfo
00000101a7bca000, tas
k 00000101a70df030)
<Nov/30 10:33 am>Stack: ffffffffa02e110a 0000000000000100
0000000000000000 00000
00000529780
<Nov/30 10:33 am>       0001000000000246 0000000000000246
000000008013feac 00000
800ffffffe0
<Nov/30 10:33 am>       0000000000000000 00000101a7bcbe88
<Nov/30 10:33 am>Call Trace:<ffffffffa02e110a>{:ib_sdp:sdp_sendmsg+724}
<fffffff
f801478b2>{queue_delayed_work+101}
<Nov/30 10:33 am>       <ffffffffa02c6200>{:ib_addr:queue_req+122}
<ffffffff802a
7ecb>{sock_sendmsg+271}
<Nov/30 10:33 am>       <ffffffff80169a61>{do_no_page+916}
<ffffffff801359a8>{au
toremove_wake_function+0}
<Nov/30 10:33 am>       <ffffffff802a7c53>{sockfd_lookup+16}
<ffffffff802a939a>{
sys_sendto+195}
<Nov/30 10:33 am>       <ffffffff801242b9>{do_page_fault+577}
<ffffffff801934c8>
{dnotify_parent+34}
<Nov/30 10:33 am>       <ffffffff80179335>{vfs_read+248}
<ffffffff8011026a>{syst
em_call+126}
<Nov/30 10:33 am>

<Nov/30 10:33 am>Code: 8b 07 48 89 fa f6 c4 80 74 3b 48 8b 57 10 8b 02
48 89 d1
f6
<Nov/30 10:33 am>RIP <ffffffff80163ff0>{put_page+0} RSP
<00000101a7bcbbc0>
<Nov/30 10:33 am>CR2: 0000000000000000
<Nov/30 10:33 am> <0>Kernel panic - not syncing: Oops

Scott Weitzenkamp
SQA and Release Manager
Server Virtualization Business Unit
Cisco Systems
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