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RE: [PING][RFC][PATCH] generic hp_timing
- From: Maria Guseva <m dot guseva at samsung dot com>
- To: libc-alpha at sourceware dot org
- Cc: 'Yury Gribov' <y dot gribov at samsung dot com>, v dot garbuzov at samsung dot com, 'Maria Guseva' <m dot guseva at samsung dot com>
- Date: Tue, 22 Sep 2015 15:57:56 +0300
- Subject: RE: [PING][RFC][PATCH] generic hp_timing
- Authentication-results: sourceware.org; auth=none
- References:
Ping.
Regards,
Maria
>Ping.
>>Hello,
>>The attached patch is a draft implementation of generic timing: via
clock_gettime, vdso or system call, where available and via gettimeofday
function call otherwise.
>>In order to eliminate performance impact in existing usages of
HP_TIMING_NOW the HP_TIMING_AVAIL is still set to 0. The generic timing is
enabled only in DL_DEBUG_STATISTICS cases where performance is not critical.
>>However I suggest it may be wrong and we can use at least vdso
clock_gettime as real HP_TIMING. And the rest probably shouldn't be even
considered as high-precision timers and should be moved from hp-timing
header to some new one.
>>The need of generic timing was discussed in "LD_DEBUG option to measure
init time" patch review:
https://sourceware.org/ml/libc-alpha/2015-08/msg00084.html
>>Proposed there new LD_DEBUG option needs HP_TIMING implementation to be
usable on Arm platform in particular.