Messages in this thread | | | Date | Sat, 12 Oct 2013 19:21:24 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: Run checksumming in parallel accross multiple alu's |
| |
* Neil Horman <nhorman@tuxdriver.com> wrote:
> Sébastien Dugué reported to me that devices implementing ipoib (which > don't have checksum offload hardware were spending a significant amount > of time computing checksums. We found that by splitting the checksum > computation into two separate streams, each skipping successive elements > of the buffer being summed, we could parallelize the checksum operation > accros multiple alus. Since neither chain is dependent on the result of > the other, we get a speedup in execution (on hardware that has multiple > alu's available, which is almost ubiquitous on x86), and only a > negligible decrease on hardware that has only a single alu (an extra > addition is introduced). Since addition in commutative, the result is > the same, only faster
This patch should really come with measurement numbers: what performance increase (and drop) did you get on what CPUs.
Thanks,
Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |