Date: Sun, 10 Dec 2017 12:45:47 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Michael Zhilin <mizhka@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: Hopefully useful: macro-controlled logger Message-ID: <20171210104547.GX2272@kib.kiev.ua> In-Reply-To: <CAF19XBL6yJLvHCn_V-0ntOXSQfbRn0ULgb1-fDCWZ8oBbd_y9g@mail.gmail.com> References: <0dd5240f-6c70-425f-7e98-7946097ea3ef@metricspace.net> <CAF19XBL6yJLvHCn_V-0ntOXSQfbRn0ULgb1-fDCWZ8oBbd_y9g@mail.gmail.com>
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On Sun, Dec 10, 2017 at 12:00:41PM +0300, Michael Zhilin wrote: > Hi Eric! > > Nice! This minimalistic and powerful approach looks very nice. > > We have similar thing in one of kernel driver: > https://github.com/freebsd/freebsd/blob/master/sys/dev/bhnd/bhnd_debug.h > > In my opinion such kind of thing is demanded. We already have ktr(4). If it is too limited for some use, it should be extended instead of adding parallel half-done implementation. Kernel printf(9) introduces too much serialization which makes it impossible to reproduce an issue sometimes (or often). Also, kernel consoles are slow due to the nature of the hardware, and serialization blocks other threads trying to log while current message is printed. ktr(4) avoids both of the problems.
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