Hisashi Hifumi wrote:
> Hi, Trond.
>
> I wrote "is_partially_uptodate" aops for nfs client named nfs_is_partially_uptodate().
> This aops checks that nfs_page is attached to a page and read IO to a page is
> within the range between wb_pgbase and wb_pgbase + wb_bytes of the nfs_page.
> If this aops succeed, we do not have to issue actual read IO to NFS server
> even if a page is not uptodate because the portion we want to read are uptodate.
> So with this patch random read/write mixed workloads or random read after random write
> workloads can be optimized and we can get performance improvement.
>
> I did benchmark test using sysbench.
>
> sysbench --num-threads=16 --max-requests=100000 --test=fileio --file-block-size=2K
> --file-total-size=200M --file-test-mode=rndrw --file-fsync-freq=0
> --file-rw-ratio=0.5 run
>
> The result was:
>
> -2.6.29-rc4
>
> Operations performed: 33356 Read, 66682 Write, 128 Other = 100166 Total
> Read 65.148Mb Written 130.24Mb Total transferred 195.39Mb (3.1093Mb/sec)
> 1591.97 Requests/sec executed
>
> Test execution summary:
> total time: 62.8391s
> total number of events: 100038
> total time taken by event execution: 841.7603
> per-request statistics:
> min: 0.0000s
> avg: 0.0084s
> max: 16.4564s
> approx. 95 percentile: 0.0446s
>
> Threads fairness:
> events (avg/stddev): 6252.3750/306.48
> execution time (avg/stddev): 52.6100/0.38
>
>
> -2.6.29-rc4 + patch
>
> Operations performed: 33346 Read, 66662 Write, 128 Other = 100136 Total
> Read 65.129Mb Written 130.2Mb Total transferred 195.33Mb (5.0113Mb/sec)
> 2565.81 Requests/sec executed
>
> Test execution summary:
> total time: 38.9772s
> total number of events: 100008
> total time taken by event execution: 339.6821
> per-request statistics:
> min: 0.0000s
> avg: 0.0034s
> max: 1.6768s
> approx. 95 percentile: 0.0200s
>
> Threads fairness:
> events (avg/stddev): 6250.5000/302.04
> execution time (avg/stddev): 21.2301/0.45
>
>
> I/O performance was significantly improved by following patch.
> Please merge my patch.
> Thanks.
>
> Signed-off-by: Hisashi Hifumi <hifumi.hisashi@xxxxxxxxxxxxx>
>
> diff -Nrup linux-2.6.29-rc5.org/fs/nfs/file.c linux-2.6.29-rc5/fs/nfs/file.c
> --- linux-2.6.29-rc5.org/fs/nfs/file.c 2009-02-16 12:31:18.000000000 +0900
> +++ linux-2.6.29-rc5/fs/nfs/file.c 2009-02-16 13:05:29.000000000 +0900
> @@ -449,6 +449,7 @@ const struct address_space_operations nf
> .releasepage = nfs_release_page,
> .direct_IO = nfs_direct_IO,
> .launder_page = nfs_launder_page,
> + .is_partially_uptodate = nfs_is_partially_uptodate,
> };
>
> static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
> diff -Nrup linux-2.6.29-rc5.org/fs/nfs/read.c linux-2.6.29-rc5/fs/nfs/read.c
> --- linux-2.6.29-rc5.org/fs/nfs/read.c 2009-02-16 12:31:18.000000000 +0900
> +++ linux-2.6.29-rc5/fs/nfs/read.c 2009-02-16 13:05:29.000000000 +0900
> @@ -599,6 +599,33 @@ out:
> return ret;
> }
>
> +int nfs_is_partially_uptodate(struct page *page, read_descriptor_t *desc,
> + unsigned long from)
> +{
> + struct inode *inode = page->mapping->host;
> + unsigned to;
> + struct nfs_page *req = NULL;
+ int ret;
> +
> + spin_lock(&inode->i_lock);
> + if (PagePrivate(page)) {
> + req = (struct nfs_page *)page_private(page);
> + if (req)
> + kref_get(&req->wb_kref);
> + }
> + spin_unlock(&inode->i_lock);
> + if (!req)
> + return 0;
> +
> + to = min_t(unsigned, PAGE_CACHE_SIZE - from, desc->count);
> + to = from + to;
> + if (from >= req->wb_pgbase && to <= req->wb_pgbase + req->wb_bytes) {
> + nfs_release_request(req);
- nfs_release_request(req);
> + ret = 1;
> + } else
+ ret = 0;
> + nfs_release_request(req);
> + return 0;
- return 0;
+ return ret;
> +}
> +
> int __init nfs_init_readpagecache(void)
> {
> nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
> diff -Nrup linux-2.6.29-rc5.org/include/linux/nfs_fs.h linux-2.6.29-rc5/include/linux/nfs_fs.h
> --- linux-2.6.29-rc5.org/include/linux/nfs_fs.h 2009-02-16 12:31:18.000000000 +0900
> +++ linux-2.6.29-rc5/include/linux/nfs_fs.h 2009-02-16 13:05:29.000000000 +0900
> @@ -506,6 +506,9 @@ extern int nfs_readpages(struct file *,
> struct list_head *, unsigned);
> extern int nfs_readpage_result(struct rpc_task *, struct nfs_read_data *);
> extern void nfs_readdata_release(void *data);
> +extern int nfs_is_partially_uptodate(struct page *, read_descriptor_t *,
> + unsigned long);
> +
>
> /*
> * Allocate nfs_read_data structures
>
> --
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