On Fri, Jul 18, 2014 at 12:20:56PM +0200, Alexander Gordeev wrote: > The performance test is not decent, though. I used "fio" random > read against a "null_blk" device sitting on top of "percpu_tags", > which is not exactly how "percpu_ida" is used. This is another > reason I am posting - an advice on how to properly test is very > appreciated. Hi Nicholas et al, I expect the best possible performance test for percpu_ida/percpu_tags would be to stress drivers/vhost/scsi.c vhost_scsi_get_tag() function. I tried to make such test by attaching ramdisk to a virtual machine (similar to https://lkml.org/lkml/2012/8/10/347) but ultimately failed to configure the necessary environment - the stock qemu does not have -vhost-scsi parameter. Could you please advice how to make this configuration exposed to guests? o- / ..................................................................... [...] o- backstores .......................................................... [...] | o- block .............................................. [Storage Objects: 0] | o- fileio ............................................. [Storage Objects: 0] | o- pscsi .............................................. [Storage Objects: 0] | o- ramdisk ............................................ [Storage Objects: 1] | o- rda .............................................. [(1.0GiB) activated] o- iscsi ........................................................ [Targets: 0] o- loopback ..................................................... [Targets: 0] o- vhost ........................................................ [Targets: 1] o- naa.5001405b171ee405 .......................................... [TPGs: 1] o- tpg1 .............................. [naa.5001405983a5b1a4, no-gen-acls] o- acls ...................................................... [ACLs: 0] o- luns ...................................................... [LUNs: 1] o- lun0 ................................................ [ramdisk/rda] Thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
