From mboxrd@z Thu Jan 1 00:00:00 1970 From: Loic Dachary Subject: Re: [PATCH 2/3] ec: make use of added aligned buffers Date: Mon, 15 Sep 2014 19:20:29 +0200 Message-ID: <54171FDD.4070701@dachary.org> References: <1410796508-28711-1-git-send-email-j@jannau.net> <1410796508-28711-2-git-send-email-j@jannau.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="CpMEPvnmSojArg235v13mejEr0E1G275C" Return-path: Received: from mail2.dachary.org ([91.121.57.175]:52544 "EHLO smtp.dmail.dachary.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753996AbaIORUg (ORCPT ); Mon, 15 Sep 2014 13:20:36 -0400 In-Reply-To: <1410796508-28711-2-git-send-email-j@jannau.net> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Janne Grunau , ceph-devel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --CpMEPvnmSojArg235v13mejEr0E1G275C Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable 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=3Dreed_sol_van,k=3D2,m=3D1. >=20 > Also prevents a misaligned buffer when bufferlist::c_str(bufferlist) > has to allocate a new buffer to provide continuous one. See bug #9408 >=20 > Signed-off-by: Janne Grunau > --- > src/erasure-code/ErasureCode.cc | 46 +++++++++++++++++++++++++--------= -------- > src/erasure-code/ErasureCode.h | 3 ++- > 2 files changed, 30 insertions(+), 19 deletions(-) >=20 > diff --git a/src/erasure-code/ErasureCode.cc b/src/erasure-code/Erasure= Code.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 &want_to_read, > } > =20 > int ErasureCode::encode_prepare(const bufferlist &raw, > - bufferlist *prepared) const > + map &encoded) const > { > unsigned int k =3D get_data_chunk_count(); > unsigned int m =3D get_chunk_count() - k; > unsigned blocksize =3D get_chunk_size(raw.length()); > - unsigned padded_length =3D blocksize * k; > - *prepared =3D raw; > - if (padded_length - raw.length() > 0) { > - bufferptr pad(padded_length - raw.length()); > - pad.zero(); > - prepared->push_back(pad); > + unsigned pad_len =3D blocksize * k - raw.length(); > + > + bufferlist prepared =3D raw; > + > + if (!prepared.is_aligned()) { > + prepared.rebuild_aligned(); > + } > + > + for (unsigned int i =3D 0; i < k - !!pad_len; i++) { > + int chunk_index =3D chunk_mapping.size() > 0 ? chunk_mapping[i] : = i; > + bufferlist &chunk =3D 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 =3D 16, k=3D12 and in of length 1550 y= ou end up with two padding chunks because the blocksize is 144. > + if (pad_len > 0) { > + int chunk_index =3D chunk_mapping.size() > 0 ? chunk_mapping[k - 1= ] : k - 1; > + bufferlist &chunk =3D 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 =3D blocksize * m; > - bufferptr coding(buffer::create_page_aligned(coding_length)); > - prepared->push_back(coding); > - prepared->rebuild_page_aligned(); > + for (unsigned int i =3D k; i < k + m; i++) { > + int chunk_index =3D chunk_mapping.size() > 0 ? chunk_mapping[i] : = i; > + bufferlist &chunk =3D encoded[chunk_index]; > + chunk.push_back(buffer::create_aligned(blocksize)); > + } > + > return 0; > } > =20 > @@ -80,15 +96,9 @@ int ErasureCode::encode(const set &want_to_enco= de, > unsigned int k =3D get_data_chunk_count(); > unsigned int m =3D get_chunk_count() - k; > bufferlist out; > - int err =3D encode_prepare(in, &out); > + int err =3D encode_prepare(in, *encoded); > if (err) > return err; > - unsigned blocksize =3D get_chunk_size(in.length()); > - for (unsigned int i =3D 0; i < k + m; i++) { > - int chunk_index =3D chunk_mapping.size() > 0 ? chunk_mapping[i] : = i; > - bufferlist &chunk =3D (*encoded)[chunk_index]; > - chunk.substr_of(out, i * blocksize, blocksize); > - } > encode_chunks(want_to_encode, encoded); > for (unsigned int i =3D 0; i < k + m; i++) { > if (want_to_encode.count(i) =3D=3D 0) > diff --git a/src/erasure-code/ErasureCode.h b/src/erasure-code/ErasureC= ode.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 &avail= able, > set *minimum); > =20 > - int encode_prepare(const bufferlist &raw, bufferlist *prepared) co= nst; > + int encode_prepare(const bufferlist &raw, > + map &encoded) const; > =20 > virtual int encode(const set &want_to_encode, > const bufferlist &in, >=20 --=20 Lo=EFc Dachary, Artisan Logiciel Libre --CpMEPvnmSojArg235v13mejEr0E1G275C Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlQXH90ACgkQ8dLMyEl6F20l6gCgnVisDJh6a8R94fOTlFwsyW3n Rr8An15Wh2ar0OgQEmUsLJlteIpD7a79 =ai4T -----END PGP SIGNATURE----- --CpMEPvnmSojArg235v13mejEr0E1G275C--