On Monday 21 December 2009, Rafael J. Wysocki wrote: > On Monday 21 December 2009, Alan Stern wrote: > > On Mon, 21 Dec 2009, Rafael J. Wysocki wrote: ... > > You should also make SCSI targets and hosts async. Hosts are added in > > drivers/scsi/hosts.c:scsi_add_host_with_dma() (in 2.6.32 this was > > named scsi_add_host()). Targets are added in > > drivers/scsi/scsi_sysfs.c:scsi_target_add(). And for thoroughness, > > SCSI devices are added in scsi_sysfs_add_sdev() in the same file. > > Thanks a lot for the pointers. I put device_enable_async_suspend() in all of these places and that resulted in major reduction of suspend time without starting the async threads upfront. Now, however, starting them upfront helps only a little, within the standard deviation from the "non-upfront" case. In turn, resume _without_ starting the async threads upfront makes a little sense on my test boxes. In fact, it only helped on the nx6325 and made things worse on the other two (I added the results from Toshiba Portege R500, but it has the same chipset as the Wind U100, ie. ICH7). The results are as follows: HP nx6325 MSI Wind U100 Toshiba Portege R500 sync suspend 1357 (+/- 35) 656 (+/- 50) 889 (+/- 29) sync resume 3027 (+/- 6) 3372 (+/- 30) 4552 (+/- 35) async suspend 1053 (+/- 50) 490 (+/- 42) 620 (+/- 52) async resume 2291 (+/- 7) 3406 (+/- 52) 4557 (+/- 26) async "upfront" suspend 1040 (+/- 35) 476 (+/- 9) 585 (+/- 29) async "upfront" resume 1787 (+/- 7) 1724 (+/- 48) 1990 (+/- 25) The raw data are at http://www.sisk.pl/kernel/data/async-suspend-updated.pdf http://www.sisk.pl/kernel/data/r500/ http://www.sisk.pl/kernel/data/nx6325/ http://www.sisk.pl/kernel/data/wind/ and the previous results were moved into http://www.sisk.pl/kernel/data/091220/ The patches used in the testing are in my async branch at http://git.kernel.org/?p=linux/kernel/git/rafael/suspend-2.6.git;a=shortlog;h=refs/heads/async The patches in this branch are not for upstream, but it's on top of the linux-next branch containing patches for the 2.6.34 merge window. ... > > Although USB host controllers aren't the longest-running devices to > > resume, they do tend to be on the longest paths. Speeding them up > > would help. One change you could try is in the patch below. > > Currently when a controller has to be reset, the root hub beneath it is > > also reset and then re-suspended. However there's no reason to suspend > > it if the PM core is only going to resume it a little bit later. The > > patch gets rid of the unnecessary suspend. Note: I haven't tested it. > > OK, I'll try it. Unfortunately it breaks the second suspend (suspend process returns error code and says that the controller was not suspended, more or less). Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
