> Subject: RE: [PATCH 1/1] scsi: storvsc: Spread interrupts when picking a > channel for I/O requests > > > From: Long Li > > Sent: Wednesday, January 31, 2018 12:23 PM > > To: Michael Kelley (EOSG) <[email protected]>; KY > > Srinivasan <[email protected]>; Stephen Hemminger > > <[email protected]>; [email protected]; > > [email protected]; [email protected]; > > [email protected]; James E . J . Bottomley > > <[email protected]> > > Subject: RE: [PATCH 1/1] scsi: storvsc: Spread interrupts when picking > > a channel for I/O requests > > > > > Subject: RE: [PATCH 1/1] scsi: storvsc: Spread interrupts when > > > picking a channel for I/O requests > > > > > > Updated/corrected two email addresses ... > > > > > > > -----Original Message----- > > > > From: Michael Kelley (EOSG) > > > > Sent: Wednesday, January 24, 2018 2:14 PM > > > > To: KY Srinivasan <[email protected]>; Stephen Hemminger > > > > <[email protected]>; [email protected]; > > > > [email protected]; [email protected]; > > > > [email protected]; [email protected]; > > > > [email protected] > > > > Cc: Michael Kelley (EOSG) <[email protected]> > > > > Subject: [PATCH 1/1] scsi: storvsc: Spread interrupts when picking > > > > a channel for I/O requests > > > > > > > > Update the algorithm in storvsc_do_io to look for a channel > > > > starting with the current CPU + 1 and wrap around (within the > > > > current NUMA node). This spreads VMbus interrupts more evenly > > > > across CPUs. Previous code always started with first CPU in the > > > > current NUMA node, skewing the interrupt load to that CPU. > > > > > > > > Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Long Li <[email protected]> > > > > --- > > > > drivers/scsi/storvsc_drv.c | 3 ++- > > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/scsi/storvsc_drv.c > > > > b/drivers/scsi/storvsc_drv.c index e07907d..f3264c4 100644 > > > > --- a/drivers/scsi/storvsc_drv.c > > > > +++ b/drivers/scsi/storvsc_drv.c > > > > @@ -1310,7 +1310,8 @@ static int storvsc_do_io(struct hv_device > *device, > > > > */ > > > > cpumask_and(&alloced_mask, &stor_device- > alloced_cpus, > > > > > > > cpumask_of_node(cpu_to_node(q_num))); > > > > - for_each_cpu(tgt_cpu, &alloced_mask) { > > > > + for_each_cpu_wrap(tgt_cpu, &alloced_mask, > > > > + outgoing_channel->target_cpu + > > > > 1) { > > > > Does it work when target_cpu is the last CPU on the system? > > > > Otherwise, looking good. > > Yes, it works. for_each_cpu_wrap() correctly wraps in the case where the > 3rd parameter ('start') is one past the end of the mask. Arguably, we > shouldn't rely on that, and should do the wrap to 0 before calling > for_each_cpu_wrap(). > > > > > > > if (tgt_cpu != > > > > outgoing_channel->target_cpu) > > > { > > > > outgoing_channel = > > > > stor_device->stor_chns[tgt_cpu]; > > > > -- > > > > 1.8.3.1 _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
