Message 209757 - Python tracker

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Author	vstinner
Recipients	gvanrossum, python-dev, vstinner
Date	2014-01-31.10:25:01
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1391163903.22.0.971212919758.issue20452@psf.upfronthosting.co.za>
In-reply-to

Content
It looks like select() and poll() in Linux < 2.6.28 has a resolution of 1/HZ, where HZ can be retrieved from os.sysconf('SC_CLK_TCK'). Since Linux 2.6.28, hrtimers are now used for timeouts. "High- (but not too high-) resolution timeouts" http://lwn.net/Articles/296578/ "What's in hrtimer.git for 2.6.28" https://lkml.org/lkml/2008/9/20/136 Attached patch improves the resolution field of selectors.BaseSelector. By the way, resolution should be a method (selector.resolution()) rather than a property, because we may query the kernel to compute the resolution, as shown in the patch.

It looks like select() and poll() in Linux < 2.6.28 has a resolution of 1/HZ, where HZ can be retrieved from os.sysconf('SC_CLK_TCK'). Since Linux 2.6.28, hrtimers are now used for timeouts.

"High- (but not too high-) resolution timeouts"
http://lwn.net/Articles/296578/

"What's in hrtimer.git for 2.6.28"
https://lkml.org/lkml/2008/9/20/136

Attached patch improves the resolution field of selectors.BaseSelector.

By the way, resolution should be a method (selector.resolution()) rather than a property, because we may query the kernel to compute the resolution, as shown in the patch.

History
Date	User	Action	Args
2014-01-31 10:25:03	vstinner	set	recipients: + vstinner, gvanrossum, python-dev
2014-01-31 10:25:03	vstinner	set	messageid: <1391163903.22.0.971212919758.issue20452@psf.upfronthosting.co.za>
2014-01-31 10:25:03	vstinner	link	issue20452 messages
2014-01-31 10:25:01	vstinner	create