On Tue, Feb 18, 2020 at 1:23 PM Yonghong Song <yhs@xxxxxx> wrote:
>
>
>
> On 2/18/20 9:25 AM, Brian Vazquez wrote:
> > Grabbing the spinlock for every bucket even if it's empty, was causing
> > significant perfomance cost when traversing htab maps that have only a
> > few entries. This patch addresses the issue by checking first the
> > bucket_cnt, if the bucket has some entries then we go and grab the
> > spinlock and proceed with the batching.
> >
> > Tested with a htab of size 50K and different value of populated entries.
> >
> > Before:
> > Benchmark Time(ns) CPU(ns)
> > ---------------------------------------------
> > BM_DumpHashMap/1 2759655 2752033
> > BM_DumpHashMap/10 2933722 2930825
> > BM_DumpHashMap/200 3171680 3170265
> > BM_DumpHashMap/500 3639607 3635511
> > BM_DumpHashMap/1000 4369008 4364981
> > BM_DumpHashMap/5k 11171919 11134028
> > BM_DumpHashMap/20k 69150080 69033496
> > BM_DumpHashMap/39k 190501036 190226162
> >
> > After:
> > Benchmark Time(ns) CPU(ns)
> > ---------------------------------------------
> > BM_DumpHashMap/1 202707 200109
> > BM_DumpHashMap/10 213441 210569
> > BM_DumpHashMap/200 478641 472350
> > BM_DumpHashMap/500 980061 967102
> > BM_DumpHashMap/1000 1863835 1839575
> > BM_DumpHashMap/5k 8961836 8902540
> > BM_DumpHashMap/20k 69761497 69322756
> > BM_DumpHashMap/39k 187437830 186551111
> >
> > Fixes: 057996380a42 ("bpf: Add batch ops to all htab bpf map")
> > Cc: Yonghong Song <yhs@xxxxxx>
> > Signed-off-by: Brian Vazquez <brianvv@xxxxxxxxxx>
>
> Thanks for the fix.
> Acked-by: Yonghong Song <yhs@xxxxxx>
Applied. Thanks
