Re: Kernel 3.0: Instant kernel crash when mounting CIFS (also crasheswith linux-3.1-rc2

From: Justin Piszcz
Date: Thu Aug 18 2011 - 14:18:21 EST




On Thu, 18 Aug 2011, Steve French wrote:

If reading files - smbclient (ftp like syntax) should be able to reach
wire speeds (assuming the server disk can keep up) and for
writing it should be similar (perhaps a little slower but it won't
use i/o sizes as large as cifs kernel client). I would expect
smbclient to/copy from Windows to be faster than Windows mount -> Samba.

I reached near wirespeeds for GigE with cifs client (writing) to
Winodws 2003/2008/r2
and Samba - but didn't have fast enough disks to test 10GigE although I expect
very good performance with that if you have fast enough server disks (and
am willing to put performance patches in, if you detect additional
changes that we should make for 10GigE - in particular allowing
more than 50 simultaneous requests).

If the registry fix for Windows 7 is in place (or if you copy to
WIndows 2008, Windows 2003, WIndows 2008r2) -
cifs kernel client is probably slightly faster for writes than alternatives,
smbclient much faster for reads.

If going the other direction (Windows client copying to/from Samba server) -
Samba 3.6 (server) with SMB2 support
turned on - is going to be faster than most alternatives.

Hi,

Downloading from an FTP Server on the windows machine:

<--- 150 Connection accepted
`file' at 418873344 (24%) 145.58M/s eta:9s [Receiving data]
`file' at 735510528 (42%) 162.93M/s eta:6s [Receiving data]
`file' at 1357185024 (78%) 172.89M/s eta:2s [Receiving data]
<--- 226 Transfer OK ---- Got EOF on data connection
---- Closing data socket
1719784995 bytes transferred in 9 seconds (181.65M/s)

Same file (via CIFS): 50MB/s

Device eth6 [10.0.1.2] (1/1):
================================================================================
Incoming: Outgoing:
Curr: 49.17 MByte/s Curr: 0.58 MByte/s
Avg: 8.76 MByte/s Avg: 0.03 MByte/s
Min: 0.00 MByte/s Min: 0.00 MByte/s
Max: 197.68 MByte/s Max: 0.86 MByte/s
Ttl: 585.87 GByte Ttl: 6.97 GByte

0.02user 4.09system 0:33.84elapsed 12%CPU (0avgtext+0avgdata 3632maxresident)k

The RAID's on both systems can achieve > 750MiB/s sustained without any
problems (benchmarked in the past) and the system has 56 PCI-e 2.0 lanes
and a cable between two 10GbE nics. Not sure where to start, Win7/box tweaks
or Linux/CIFS options?

Again, Samba -> Linux = 500MiB/s, so FTP > 3x faster than CIFS.
I know NFS gets a lot of testing (never had an issue with it/performance/etc)

However, regarding CIFS-- is there a test suite/or benchmark pack the CIFS developers use to make sure everything is working in order?

Justin.


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