Hi I don't think there is any problem to let the read request to flow through, since in the original code, In order to decrypt the read requests, we create a new task (workingQ) that perform the decrypt, and doesn't notify any other task when it finish, except for the dec_pending(io,r) which I moved to the read callback.
Regards Ronen Shitrit Marvell Semiconductor Israel Ltd -----Original Message----- From: Evgeniy Polyakov [mailto:[EMAIL PROTECTED] Sent: Wednesday, September 07, 2005 10:36 AM To: Ronen Shitrit Cc: [EMAIL PROTECTED]; linux-crypto@vger.kernel.org Subject: Re: Dm-crypt patch for OCF On Tue, Sep 06, 2005 at 09:20:42PM +0300, Ronen Shitrit ([EMAIL PROTECTED]) wrote: > Hi Hello, Ronen. I have some doubts - you only wait on write request, but allow read request to flow through - when doind read request it does not mean, that dm-crypt is the last target, it can be even freed when your read callback will be called. And according to crypto sessions - I was confused by this name, and did not understood you from the first point. I want to say, that acrypto does not have such crypto session like OCF has. It only has crypto requests in OCF terminology, since it does not require special controlling strucutre on top of it. I will describe it in more details in different thread. > I improved the first patch, see attached. > > Dm-crypt: > -)On the encrypt(write) side we first allocate a new buffer then we > encrypt (using crypt_convert) the src buffer to the new buffer, we > send it > to be written through the generic_make_request(clone), then when the > clone->bi_end_io is called we free the buffer and the io. > -)On the decrypt(read) side we first read the buffer to the source > through the generic_make_request(clone), then when the clone->bi_end_io > is called, we create a new working thread which will decrypt (using > crypt_convert) the buffer and free the io. > > In the first patch, for each crypt_convert operation we send all the > sectors of the context to be encrypt/decrypt to the OCF, and then we > are waiting for A completion of all of these sectors before returning > from crypt_convert, i.e. we get a limitation that only one > encrypt/decrypt crypt_convert operation can occur in parallel. > > In the attached new patch, I removed this limitation for the > decrypt(read) crypt_convert, > By doing this I can see that when running the Bonnie benchmark, I get > better performance for the read/rewrite tests. > > The same approach can be used for the encrypt(write) crypt_convert, it > is a little bit more complicated then the decrypt(read), maybe I will > try to implement it in future patches. > > I also noticed that sometimes I get 2 encrypt(write) crypt_convert in > parallel?!?!, that why I moved the wr_pending into a separate > structure, > > which is allocated per write request. > This change affected the write performance only in a bit, less then 1%. > > btw - this patch is a patch for kernel 2.6.12, with OCF 20050630 patch > applied on it. > same tests were used as for the first patch. > > Regards > > Ronen Shitrit > Marvell Semiconductor Israel Ltd > > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Ronen Shitrit > Sent: Monday, September 05, 2005 6:33 PM > To: [EMAIL PROTECTED]; linux-crypto@vger.kernel.org > Cc: Evgeniy Polyakov; David McCullough > Subject: Dm-crypt patch for OCF > > Hi all > > Attached is a patch for the dm_crypt HD encryption which use the OCF. > The patch includes a new Kconfig configuration option for > OCF_DM_CRYPT, When choosing this option the dm_crypt will use the OCF > for dm_crypt sector encryption/decryption, When using the essiv mode, > the essiv generation will use the kernel cryptoAPIs. > Currently this patch support the following encryption algorithms: > DES-CBC, 3DES-CBC and AES-CBC. > > I tested this driver using AES-CBC, with OCF SW driver, it seems stable. > I used the Bonnie benchmark to get some statistics: > http://www.textuality.com/bonnie/ > The bandwidth performance are much better when using the OCF dm_crypt. > This might be explained since Bonnie is using a large blocks of io > (crypt_convert get contexts of 512byte * 256), which cause the > dm_crypt to Q few requests at a time, and this "multi tasking", cause > that the HD and the CPU "bandwidth" are exploit in a better way. (I > assume) > > When using mkfs.ext2 on large partition I see that the OCF dm_crypt > requires about 7% more time then when using the standard dm_crypt. > This can be explained since the mkfs.ext2 is mostly using writes of > small blocks (crypt_convert get contexts of 512byte * 8), Which cause > that we gets less "multi tasking", and as explained below the write > request are not optimized in this patch. > > Currently the dm_crypt is implemented in a way that: for decryption > (read requests), it is using the source buffer itself, While for the > encryption (write requests), it is using a different buffer. > The current implementation of the OCF only support encryption on the > source buffer, which is not efficient for this case, therefore this > patch has overhead of copying the buffers to be encrypted. > > > Thanks to Evgeniy Polyakov for the Acrypto patch reference. > > Regards > > Ronen Shitrit > Marvell Semiconductor Israel Ltd > > _______________________________________________ > > Subscription: http://lists.logix.cz/mailman/listinfo/cryptoapi > List archive: http://lists.logix.cz/pipermail/cryptoapi -- Evgeniy Polyakov - To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
