On Mon, 15 Sep 2014, Ma, Jianpeng wrote: > If we modify bufferlist::c_str() to bufferlist::c_str(bool align). > If (align) > Posix_memalign(data, CEPH_PAGE_SIZE, len) > Else > Origin code. Alignment isn't really a bool, it's an int. c_str(int align=1) ? sage > > I think this is simple and correctly code. > > Jianpeng > Thanks! > > > -----Original Message----- > > From: ceph-devel-owner@xxxxxxxxxxxxxxx > > [mailto:ceph-devel-owner@xxxxxxxxxxxxxxx] On Behalf Of Loic Dachary > > Sent: Tuesday, September 16, 2014 1:20 AM > > To: Janne Grunau; ceph-devel@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH 2/3] ec: make use of added aligned buffers > > > > Hi Janne, > > > > See below: > > > > On 15/09/2014 17:55, Janne Grunau wrote: > > > Requiring page aligned buffers and realigning the input if necessary > > > creates measurable oberhead. ceph_erasure_code_benchmark is ~30% > > > faster with this change for technique=reed_sol_van,k=2,m=1. > > > > > > Also prevents a misaligned buffer when bufferlist::c_str(bufferlist) > > > has to allocate a new buffer to provide continuous one. See bug #9408 > > > > > > Signed-off-by: Janne Grunau <j@xxxxxxxxxx> > > > --- > > > src/erasure-code/ErasureCode.cc | 46 > > > +++++++++++++++++++++++++---------------- > > > src/erasure-code/ErasureCode.h | 3 ++- > > > 2 files changed, 30 insertions(+), 19 deletions(-) > > > > > > diff --git a/src/erasure-code/ErasureCode.cc > > > b/src/erasure-code/ErasureCode.cc index 5953f49..078f60b 100644 > > > --- a/src/erasure-code/ErasureCode.cc > > > +++ b/src/erasure-code/ErasureCode.cc > > > @@ -54,22 +54,38 @@ int > > ErasureCode::minimum_to_decode_with_cost(const > > > set<int> &want_to_read, } > > > > > > int ErasureCode::encode_prepare(const bufferlist &raw, > > > - bufferlist *prepared) const > > > + map<int, bufferlist> &encoded) > > const > > > { > > > unsigned int k = get_data_chunk_count(); > > > unsigned int m = get_chunk_count() - k; > > > unsigned blocksize = get_chunk_size(raw.length()); > > > - unsigned padded_length = blocksize * k; > > > - *prepared = raw; > > > - if (padded_length - raw.length() > 0) { > > > - bufferptr pad(padded_length - raw.length()); > > > - pad.zero(); > > > - prepared->push_back(pad); > > > + unsigned pad_len = blocksize * k - raw.length(); > > > + > > > + bufferlist prepared = raw; > > > + > > > + if (!prepared.is_aligned()) { > > > + prepared.rebuild_aligned(); > > > + } > > > + > > > + for (unsigned int i = 0; i < k - !!pad_len; i++) { > > > + int chunk_index = chunk_mapping.size() > 0 ? chunk_mapping[i] : i; > > > + bufferlist &chunk = encoded[chunk_index]; > > > + chunk.substr_of(prepared, i * blocksize, blocksize); } > > > > It is possible for more than one chunk to be padding. It's a border case but... for > > instance with alignment = 16, k=12 and in of length 1550 you end up with two > > padding chunks because the blocksize is 144. > > > > > + if (pad_len > 0) { > > > + int chunk_index = chunk_mapping.size() > 0 ? chunk_mapping[k - 1] : k - > > 1; > > > + bufferlist &chunk = encoded[chunk_index]; > > > + bufferptr padded(buffer::create_aligned(blocksize)); > > > + raw.copy((k - 1) * blocksize, blocksize - pad_len, padded.c_str()); > > > + padded.zero(blocksize - pad_len, pad_len); > > > + chunk.push_back(padded); > > > } > > > - unsigned coding_length = blocksize * m; > > > - bufferptr coding(buffer::create_page_aligned(coding_length)); > > > - prepared->push_back(coding); > > > - prepared->rebuild_page_aligned(); > > > + for (unsigned int i = k; i < k + m; i++) { > > > + int chunk_index = chunk_mapping.size() > 0 ? chunk_mapping[i] : i; > > > + bufferlist &chunk = encoded[chunk_index]; > > > + chunk.push_back(buffer::create_aligned(blocksize)); > > > + } > > > + > > > return 0; > > > } > > > > > > @@ -80,15 +96,9 @@ int ErasureCode::encode(const set<int> > > &want_to_encode, > > > unsigned int k = get_data_chunk_count(); > > > unsigned int m = get_chunk_count() - k; > > > bufferlist out; > > > - int err = encode_prepare(in, &out); > > > + int err = encode_prepare(in, *encoded); > > > if (err) > > > return err; > > > - unsigned blocksize = get_chunk_size(in.length()); > > > - for (unsigned int i = 0; i < k + m; i++) { > > > - int chunk_index = chunk_mapping.size() > 0 ? chunk_mapping[i] : i; > > > - bufferlist &chunk = (*encoded)[chunk_index]; > > > - chunk.substr_of(out, i * blocksize, blocksize); > > > - } > > > encode_chunks(want_to_encode, encoded); > > > for (unsigned int i = 0; i < k + m; i++) { > > > if (want_to_encode.count(i) == 0) diff --git > > > a/src/erasure-code/ErasureCode.h b/src/erasure-code/ErasureCode.h > > > index 7aaea95..62aa383 100644 > > > --- a/src/erasure-code/ErasureCode.h > > > +++ b/src/erasure-code/ErasureCode.h > > > @@ -46,7 +46,8 @@ namespace ceph { > > > const map<int, int> > > &available, > > > set<int> *minimum); > > > > > > - int encode_prepare(const bufferlist &raw, bufferlist *prepared) const; > > > + int encode_prepare(const bufferlist &raw, > > > + map<int, bufferlist> &encoded) const; > > > > > > virtual int encode(const set<int> &want_to_encode, > > > const bufferlist &in, > > > > > > > -- > > Lo?c Dachary, Artisan Logiciel Libre > > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
