From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1SUcHK-0003P8-U3 for barebox@lists.infradead.org; Wed, 16 May 2012 11:20:28 +0000 Date: Wed, 16 May 2012 13:20:25 +0200 From: Sascha Hauer Message-ID: <20120516112025.GR30400@pengutronix.de> References: <20120515192934.GM30400@pengutronix.de> <1337148616-13639-1-git-send-email-j.weitzel@phytec.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1337148616-13639-1-git-send-email-j.weitzel@phytec.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH] ramfs: rember last accessed chunk To: Jan Weitzel Cc: barebox@lists.infradead.org On Wed, May 16, 2012 at 08:10:16AM +0200, Jan Weitzel wrote: > Writing big files takes longer and longer because of the chunk list > By storing a pointer of the recent used chunk in the inode, access times are > improved. > Testet on with tftp 10M: > OMAP4 chunk size 4096: 12244ms 8192: 4239ms > patched 2647ms 2785ms > i.MX35 chunk size 8192: 7225ms > patched 2691ms > > No impact on much smaller files seen > > Signed-off-by: Jan Weitzel Applied, thanks Sascha > --- > v2: I will use checkpatch > > fs/ramfs.c | 47 +++++++++++++++++++++++++++++++++++++---------- > 1 files changed, 37 insertions(+), 10 deletions(-) > > diff --git a/fs/ramfs.c b/fs/ramfs.c > index 83ab6df..cec5e76 100644 > --- a/fs/ramfs.c > +++ b/fs/ramfs.c > @@ -48,6 +48,10 @@ struct ramfs_inode { > > ulong size; > struct ramfs_chunk *data; > + > + /* Points to recently used chunk */ > + int recent_chunk; > + struct ramfs_chunk *recent_chunkp; > }; > > struct ramfs_priv { > @@ -297,6 +301,35 @@ static int ramfs_close(struct device_d *dev, FILE *f) > return 0; > } > > +static struct ramfs_chunk *ramfs_find_chunk(struct ramfs_inode *node, int chunk) > +{ > + struct ramfs_chunk *data; > + int left = chunk; > + > + if (chunk == 0) > + return node->data; > + > + if (node->recent_chunk == chunk) > + return node->recent_chunkp; > + > + if (node->recent_chunk < chunk && node->recent_chunk != 0) { > + /* Start at last known chunk */ > + data = node->recent_chunkp; > + left -= node->recent_chunk; > + } else { > + /* Start at first chunk */ > + data = node->data; > + } > + > + while (left--) > + data = data->next; > + > + node->recent_chunkp = data; > + node->recent_chunk = chunk; > + > + return data; > +} > + > static int ramfs_read(struct device_d *_dev, FILE *f, void *buf, size_t insize) > { > struct ramfs_inode *node = (struct ramfs_inode *)f->inode; > @@ -311,11 +344,7 @@ static int ramfs_read(struct device_d *_dev, FILE *f, void *buf, size_t insize) > debug("%s: reading from chunk %d\n", __FUNCTION__, chunk); > > /* Position ourself in stream */ > - data = node->data; > - while (chunk) { > - data = data->next; > - chunk--; > - } > + data = ramfs_find_chunk(node, chunk); > ofs = f->pos % CHUNK_SIZE; > > /* Read till end of current chunk */ > @@ -364,11 +393,7 @@ static int ramfs_write(struct device_d *_dev, FILE *f, const void *buf, size_t i > debug("%s: writing to chunk %d\n", __FUNCTION__, chunk); > > /* Position ourself in stream */ > - data = node->data; > - while (chunk) { > - data = data->next; > - chunk--; > - } > + data = ramfs_find_chunk(node, chunk); > ofs = f->pos % CHUNK_SIZE; > > /* Write till end of current chunk */ > @@ -429,6 +454,8 @@ static int ramfs_truncate(struct device_d *dev, FILE *f, ulong size) > ramfs_put_chunk(data); > data = tmp; > } > + if (node->recent_chunk > newchunks) > + node->recent_chunk = 0; > } > > if (newchunks > oldchunks) { > -- > 1.7.0.4 > > > _______________________________________________ > barebox mailing list > barebox@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/barebox > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox