[Bug 1601836] [NEW] Openssl libcrypto performance issue

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== Comment: #0 - Bastian Pfeifer <Bastian.Pfeifer at de.ibm.com> - 2016-04-22 03:37:03 ==
---Problem Description---
Performance problem with s390x assembly code in the openssl libcrypto library:
CPACF functions such as SHA, AES ... queries the CPACF facility bits too often.

Problematic code can be found here:
https://github.com/openssl/openssl/blob/master/crypto/sha/asm/sha1-s390x.pl

What happens is that for every e.g SHA1 call the code first tests if the
HW function is available. That's the case for all the CPACF functions.

However what the lib should do is to query only once, safe the value and
then use the function. The problem is that the Hipervisor in certain
scenarios is required to intercept the query instructions, which makes
this really expensive.

 
Contact Information = Bastian.Pfeifer at de.ibm.com 
 
---uname output---
4.4.0-18-generic #34-Ubuntu SMP 
 
Machine Type = 2964, 701 NC9 
 
---Debugger---
A debugger is not configured
 
---Steps to Reproduce---
 n/a
 
Userspace tool common name: OpenSSL 
 
The userspace tool has the following bit modes: 64-bit 

Userspace rpm: OpenSSL 1.0.2g  1 Mar 2016

Userspace tool obtained from project website:  na 
 
*Additional Instructions for Bastian.Pfeifer at de.ibm.com:
-Attach ltrace and strace of userspace application.

== Comment: #8 - Bastian Pfeifer <Bastian.Pfeifer at de.ibm.com> - 2016-06-02 07:05:00 ==
We performed tests on the new SHA,AES and GHASH code and report performance improvements especially for SHA (up to 20%).

Here are the links to the new s390x assembly code which should be used
to create patches for the UBUNTU specific openssl versions.

1)
https://github.com/openssl/openssl/blob/master/crypto/s390xcpuid.S
2)
https://github.com/openssl/openssl/blob/master/crypto/s390xcap.c
3)
https://github.com/openssl/openssl/blob/master/crypto/sha/asm/sha1-s390x.pl
4)
https://github.com/openssl/openssl/blob/master/crypto/sha/asm/sha512-s390x.pl
5)
https://github.com/openssl/openssl/blob/master/crypto/aes/asm/aes-s390x.pl
6)
https://github.com/openssl/openssl/blob/master/crypto/modes/asm/ghash-s390x.pl

In case of AES I was forced to change the following code in aes-s390x.pl

.globl	AES_set_decrypt_key
.type	AES_set_decrypt_key,\@function

goes to

.globl	private_AES_set_decrypt_key
.type	        private_AES_set_decrypt_key,\@function

This was done for 'AES_set_encrypt_key as well; to be consistent with
the openssl code which comes with UBUNTU. For my performance tests this
worked properly and I checked the CPACF counter with the tool
'cpacfstats'.

** Affects: openssl (Ubuntu)
     Importance: Undecided
     Assignee: Skipper Bug Screeners (skipper-screen-team)
         Status: New


** Tags: architecture-s39064 bugnameltc-140645 severity-high targetmilestone-inin16041
-- 
Openssl libcrypto performance issue
https://bugs.launchpad.net/bugs/1601836
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