[dpdk-dev] hash: optimize the softrss computation
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Commit Message
Use rte_bsf32 and fast bit unset operation to optimize the softrss computation.
The following measurements shows improvement over the default
softrss computation function.
tuple lens old(cycles) new(cycles)
3 1225 337
9 3743 992
Signed-off-by: Yangchao Zhou <zhouyates@gmail.com>
---
lib/librte_hash/rte_thash.h | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
Comments
Hi,
2017-08-22 15:02 GMT+03:00 Yangchao Zhou <zhouyates@gmail.com>:
> Use rte_bsf32 and fast bit unset operation to optimize the softrss
> computation.
> The following measurements shows improvement over the default
> softrss computation function.
>
> tuple lens old(cycles) new(cycles)
> 3 1225 337
> 9 3743 992
>
> Signed-off-by: Yangchao Zhou <zhouyates@gmail.com>
> ---
> lib/librte_hash/rte_thash.h | 22 ++++++++++------------
> 1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/lib/librte_hash/rte_thash.h b/lib/librte_hash/rte_thash.h
> index 2fffd61..4fa5e07 100644
> --- a/lib/librte_hash/rte_thash.h
> +++ b/lib/librte_hash/rte_thash.h
> @@ -207,15 +207,14 @@ static inline uint32_t
> rte_softrss(uint32_t *input_tuple, uint32_t input_len,
> const uint8_t *rss_key)
> {
> - uint32_t i, j, ret = 0;
> + uint32_t i, j, map, ret = 0;
>
> for (j = 0; j < input_len; j++) {
> - for (i = 0; i < 32; i++) {
> - if (input_tuple[j] & (1 << (31 - i))) {
> - ret ^= rte_cpu_to_be_32(((const uint32_t
> *)rss_key)[j]) << i |
> + for (map = input_tuple[j]; map; map &= (map - 1)) {
> + i = rte_bsf32(map);
> + ret ^= rte_cpu_to_be_32(((const uint32_t
> *)rss_key)[j]) << (31 - i) |
> (uint32_t)((uint64_t)(rte_cpu_to_be_32(((const
> uint32_t *)rss_key)[j + 1])) >>
> - (32 - i));
> - }
> + (i + 1));
> }
> }
> return ret;
> @@ -238,14 +237,13 @@ static inline uint32_t
> rte_softrss_be(uint32_t *input_tuple, uint32_t input_len,
> const uint8_t *rss_key)
> {
> - uint32_t i, j, ret = 0;
> + uint32_t i, j, map, ret = 0;
>
> for (j = 0; j < input_len; j++) {
> - for (i = 0; i < 32; i++) {
> - if (input_tuple[j] & (1 << (31 - i))) {
> - ret ^= ((const uint32_t *)rss_key)[j] << i
> |
> - (uint32_t)((uint64_t)(((const
> uint32_t *)rss_key)[j + 1]) >> (32 - i));
> - }
> + for (map = input_tuple[j]; map; map &= (map - 1)) {
> + i = rte_bsf32(map);
> + ret ^= ((const uint32_t *)rss_key)[j] << (31 - i) |
> + (uint32_t)((uint64_t)(((const uint32_t
> *)rss_key)[j + 1]) >> (i + 1));
> }
> }
> return ret;
> --
> 2.7.4
>
>
Looks good for me. Thanks!
Reviewed-by: Medvedkin Vladimir <medvedkinv@gmail.com>
Hi,
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Vladimir
> Medvedkin
> Sent: Tuesday, August 22, 2017 4:57 PM
> To: Yangchao Zhou <zhouyates@gmail.com>
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] hash: optimize the softrss computation
>
> Hi,
>
> 2017-08-22 15:02 GMT+03:00 Yangchao Zhou <zhouyates@gmail.com>:
>
> > Use rte_bsf32 and fast bit unset operation to optimize the softrss
> > computation.
> > The following measurements shows improvement over the default softrss
> > computation function.
> >
> > tuple lens old(cycles) new(cycles)
> > 3 1225 337
> > 9 3743 992
> >
> > Signed-off-by: Yangchao Zhou <zhouyates@gmail.com>
Commit message is a bit long. Could you wrap it to have less than 75 characters per line?
Although, the patch itself has lines with more than 90 characters, which should be avoided:
http://dpdk.org/ml/archives/test-report/2017-August/027283.html
Last thing, the "Reviewed-by" has an extra space, before the name.
Thanks,
Pablo
> >
> Looks good for me. Thanks!
>
> Reviewed-by: Medvedkin Vladimir <medvedkinv@gmail.com>
>
> --
> Regards,
> Vladimir
22/09/2017 17:33, De Lara Guarch, Pablo:
> From: Vladimir Medvedkin
> > 2017-08-22 15:02 GMT+03:00 Yangchao Zhou <zhouyates@gmail.com>:
> >
> > > Use rte_bsf32 and fast bit unset operation to optimize the softrss
> > > computation.
> > > The following measurements shows improvement over the default softrss
> > > computation function.
> > >
> > > tuple lens old(cycles) new(cycles)
> > > 3 1225 337
> > > 9 3743 992
> > >
> > > Signed-off-by: Yangchao Zhou <zhouyates@gmail.com>
>
> Commit message is a bit long. Could you wrap it to have less than 75 characters per line?
> Although, the patch itself has lines with more than 90 characters, which should be avoided:
>
> http://dpdk.org/ml/archives/test-report/2017-August/027283.html
>
> Last thing, the "Reviewed-by" has an extra space, before the name.
Applied, thanks
@@ -207,15 +207,14 @@ static inline uint32_t
rte_softrss(uint32_t *input_tuple, uint32_t input_len,
const uint8_t *rss_key)
{
- uint32_t i, j, ret = 0;
+ uint32_t i, j, map, ret = 0;
for (j = 0; j < input_len; j++) {
- for (i = 0; i < 32; i++) {
- if (input_tuple[j] & (1 << (31 - i))) {
- ret ^= rte_cpu_to_be_32(((const uint32_t *)rss_key)[j]) << i |
+ for (map = input_tuple[j]; map; map &= (map - 1)) {
+ i = rte_bsf32(map);
+ ret ^= rte_cpu_to_be_32(((const uint32_t *)rss_key)[j]) << (31 - i) |
(uint32_t)((uint64_t)(rte_cpu_to_be_32(((const uint32_t *)rss_key)[j + 1])) >>
- (32 - i));
- }
+ (i + 1));
}
}
return ret;
@@ -238,14 +237,13 @@ static inline uint32_t
rte_softrss_be(uint32_t *input_tuple, uint32_t input_len,
const uint8_t *rss_key)
{
- uint32_t i, j, ret = 0;
+ uint32_t i, j, map, ret = 0;
for (j = 0; j < input_len; j++) {
- for (i = 0; i < 32; i++) {
- if (input_tuple[j] & (1 << (31 - i))) {
- ret ^= ((const uint32_t *)rss_key)[j] << i |
- (uint32_t)((uint64_t)(((const uint32_t *)rss_key)[j + 1]) >> (32 - i));
- }
+ for (map = input_tuple[j]; map; map &= (map - 1)) {
+ i = rte_bsf32(map);
+ ret ^= ((const uint32_t *)rss_key)[j] << (31 - i) |
+ (uint32_t)((uint64_t)(((const uint32_t *)rss_key)[j + 1]) >> (i + 1));
}
}
return ret;