Date: Tue, 18 Sep 2007 01:25:52 -0700 (PDT) From: Jeff Roberson <jroberson@chesapeake.net> To: Kostik Belousov <kostikbel@gmail.com> Cc: arch@freebsd.org Subject: Re: Changing p_swtime and td_slptime to ticks Message-ID: <20070918012543.Y558@10.0.0.1> In-Reply-To: <20070918043335.GR79542@deviant.kiev.zoral.com.ua> References: <20070917165657.B558@10.0.0.1> <20070918043335.GR79542@deviant.kiev.zoral.com.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, 18 Sep 2007, Kostik Belousov wrote: > On Mon, Sep 17, 2007 at 05:05:57PM -0700, Jeff Roberson wrote: >> Enclosed is a patch that fixes swapping with ULE. ULE has never properly >> set p_swtime and td_slptime which are used by the swapout/swapin code to >> select the appropriate thread to swap. >> >> In 4BSD these two variables are increment once per-second as schedcpu() >> iterates over all threads. ULE does not have a once per-second loop >> iterating over all threads. So I have changed p_swtime to p_swtick and >> td_slptime to td_slptick. These record the value of 'ticks' when the >> thread slept or was last swapped in or out. >> >> For backwards compatibility I leave the values in kinfo_proc with the >> legacy meaning by subtracting from ticks and dividing by hz. I perform a >> similar transformation in the swapout code to convert to seconds. This >> change does make it possible to use sub-second granular decisions in the >> swap code, however I'm not sure if that's really necessary. >> >> So that I did not disturb the 4BSD mechanism I kept the original >> td_slptime in the td_sched area. It should be possible to use td_slptick >> directly but especially this close to release I did not want to change >> 4BSD. >> >> Feedback and testing welcome. > > Purely cosmetic request: please make the ticks and hz variables in the > libkvm/kvm_proc.c static. Or, even better, move it into the struct __kvm. > Thanks, will do. Jeff
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20070918012543.Y558>