FUJITA Tomonori wrote: > On Thu, 27 May 2010 17:10:43 -0300 > Daniel Henrique Debonzi <debonzi at linux.vnet.ibm.com> wrote: > >> FUJITA Tomonori wrote: >>> On Tue, 18 May 2010 16:21:00 -0300 >>> Daniel Henrique Debonzi <debonzi at linux.vnet.ibm.com> wrote: >>> >>>> One idea to solve it and don't make necessary to touch all backing >>>> stores to avoid this issue is to create a new template like bs_rdrw_sync >>>> O_SYNC and O_DIRECT flags on open, and don't have the options as this >>>> patch does. This way I got want I am interested in and don't need to >>>> involve all the other stuff. What are your thoughts about it? >>> Or a new option to touch only bs_rdrw. >>> >>> However, I want to know why you want to use O_SYNC and O_DIRECT. >>> >>> - what's the advantage of O_SYNC compared with the current approach >>> (sync_file after write)? notably faster? >> We would like to be able to control those flags because for our case it >> has better performance. Some tests done recently showed that we can get >> good better results when using O_DIRECT than sync_file. > > I see. Thanks for the explanation. > > As we discussed, "--bsoflags" can't be applied to all the bs modes > equally (e.g. bs_aio can use only O_DIRECT). But I guess that creating > multiple options such as --bsoflags_rw, --bsoflags_aio, etc is too > overdoing. > > I'll take the approach add only "--bsoflags". --bsoflags="async > direct" is not consistent with the other options. Let's use "," like > --bsoflags="async,direct". I can't use "," because it is the separator used for the options --bstype,--bsoflags,etc. If I use it, the second parameter if existente (like sync,direct) will not be used right. I used ":" once it is also used for portals (IP:port). > > I don't think that we need "none" or "async". Let's support "sync" and > "direct". The async option doesn't exist. It only have sync and direct. The none option is available only for update. Lets say someone created a target with sync, and for some reason he doesn't want sync anymore. He can tgtadm --op update --mode logicalunit --tid 1 --lun 1 --params online=0 tgtadm --op update --mode logicalunit --tid 1 --lun 1 --params\ bsoflags="none" to clean up the bsoflags. I put this changes in a separate patch, so you can drop it if you think it is not necessary. > > Can you please send the updated patch? I will send the patchs to the list soon. Thanks, Daniel Debonzi -- To unsubscribe from this list: send the line "unsubscribe stgt" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html |