Date: Tue, 18 Sep 2007 07:33:35 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: Jeff Roberson <jroberson@chesapeake.net> Cc: arch@freebsd.org Subject: Re: Changing p_swtime and td_slptime to ticks Message-ID: <20070918043335.GR79542@deviant.kiev.zoral.com.ua> In-Reply-To: <20070917165657.B558@10.0.0.1> References: <20070917165657.B558@10.0.0.1>
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[-- Attachment #1 --] 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. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQFG71UeC3+MBN1Mb4gRAhVLAJ4o2OWJfJJhUKRmIyGwrBArUvjO1wCguCF2 W1KjYYG1qcDbpc5l82GZBTE= =4GbX -----END PGP SIGNATURE-----
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