This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: New rwlock committed -- enabling elision for it needs better default tuning first
- From: Torvald Riegel <triegel at redhat dot com>
- To: GLIBC Devel <libc-alpha at sourceware dot org>
- Cc: Siddhesh Poyarekar <siddhesh at sourceware dot org>, "Kleen, Andi" <andi dot kleen at intel dot com>, Stefan Liebler <stli at linux dot vnet dot ibm dot com>, Tulio Magno Quites Machado Filho <tuliom at linux dot vnet dot ibm dot com>, "Senkevich, Andrew" <andrew dot senkevich at intel dot com>
- Date: Tue, 10 Jan 2017 12:37:56 +0100
- Subject: Re: New rwlock committed -- enabling elision for it needs better default tuning first
- Authentication-results: sourceware.org; auth=none
- References: <1484048020.5606.172.camel@redhat.com>
On Tue, 2017-01-10 at 12:33 +0100, Torvald Riegel wrote:
> When testing on x86_64 TSX, my first guess for a workload that may test
> the quality of the adaption code and the default tuning parameters
> turned out to be a case where elision failed and produces significantly
> worse performance than the base algorithm (in particular, worse
> scalability). All this did was add transaction conflicts in readers;
> this isn't an artificial special case, but can easily happen through
> things like false sharing.
Here are the results:
https://www.sourceware.org/ml/libc-alpha/2016-12/msg01100.html