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Re: [PATCH] PowerPC: modf optimization
- From: Siddhesh Poyarekar <siddhesh dot poyarekar at gmail dot com>
- To: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- Cc: Andreas Jaeger <aj at suse dot com>, "GNU C. Library" <libc-alpha at sourceware dot org>
- Date: Thu, 28 Mar 2013 09:16:30 +0530
- Subject: Re: [PATCH] PowerPC: modf optimization
- References: <51508CA8 dot 5090203 at linux dot vnet dot ibm dot com> <515091DD dot 5030504 at suse dot com> <51509695 dot 7020508 at linux dot vnet dot ibm dot com> <CAAHN_R3H+6gxbCRWqGapdz5JGJhfVLePqfo08P4xGkaDMXRRUg at mail dot gmail dot com> <5152F9C4 dot 1000705 at linux dot vnet dot ibm dot com>
On 27 March 2013 19:23, Adhemerval Zanella <azanella@linux.vnet.ibm.com> wrote:
> Ok, here it an updated version using the benchtest framework. Using it I got:
>
> PATCH - m32: modf: ITERS:200000: TOTAL:0.00169022s, MAX:16.982ns, MIN:7.118ns, 1.18328e+08 iter/s
> MASTER: modf: ITERS:200000: TOTAL:0.00307463s, MAX:18.642ns, MIN:13.8ns, 6.50484e+07 iter/s
>
> PATCH - m64: modf: ITERS:200000: TOTAL:0.0011649s, MAX:8.36ns, MIN:5.458ns, 1.71688e+08 iter/s
> MASTER modf: ITERS:200000: TOTAL:0.00340596s, MAX:21.344ns, MIN:16.85ns, 5.87206e+07 iter/s
Could you increase the iterations to around 5e8? That'll give the
function a total runtime of a few seconds, which should offset the
syscall lag for architectures where clock_gettime does a syscall.
> --- /dev/null
> +++ b/benchtests/bench-modf.c
This is neat; I hadn't thought about this kind of use case when I
wrote it. Could you document it in the Makefile?
Thanks,
Siddhesh
--
http://siddhesh.in