lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:	Fri, 15 Feb 2008 09:52:01 +0800
From:	"Zhang, Yanmin" <>
Cc:	LKML <>,
Subject: tbench regression in 2.6.25-rc1

Comparing with kernel 2.6.24, tbench result has regression with

1) On 2 quad-core processor stoakley: 4%.
2) On 4 quad-core processor tigerton: more than 30%.

bisect located below patch.

b4ce92775c2e7ff9cf79cca4e0a19c8c5fd6287b is first bad commit
commit b4ce92775c2e7ff9cf79cca4e0a19c8c5fd6287b
Author: Herbert Xu <>
Date:   Tue Nov 13 21:33:32 2007 -0800

    [IPV6]: Move nfheader_len into rt6_info
    The dst member nfheader_len is only used by IPv6.  It's also currently
    creating a rather ugly alignment hole in struct dst.  Therefore this patch
    moves it from there into struct rt6_info.

As tbench uses ipv4, so the patch's real impact on ipv4 is it deletes
nfheader_len in dst_entry. It might change cache line alignment.

To verify my finding, I just added nfheader_len back to dst_entry in 2.6.25-rc1
and reran tbench on the 2 machines. Performance could be recovered completely.

I started cpu_number*2 tbench processes. On my 16-core tigerton:
#./tbench_srv &
#./tbench 32


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists