Re: increasing scsi_max_sg / max_segments for scsi writes/reads
Hi , I tried working on scsi_malloc to increase burst size , but to no avail ..all I got was hanged system every time I started data transfers! Has anyone worked on scsi_malloc , I am still trying to figure out what changes were made in 2.6 to overcome this problem of limited bursts. Any pointers are very greatly welcome...I have never worked on this part of the code before . Sai --- "Randy.Dunlap" <[EMAIL PROTECTED]> wrote: > On Sat, 9 Apr 2005 19:35:52 -0700 (PDT) sai > narasimhamurthy wrote: > > | Hi, > | I had posted a question on increasing the scsi > | read/write sectors per command. I figured out > some of > | the things, but many questions still exist. > | > | I was wondering why the maximum writes I could get > | from a single scsi write command could never > exceed > | 204 > | 4096B segments . I traced it to : > | > | static const int scsi_max_sg = PAGE_SIZE / > | sizeof(struct scatterlist) > | > | in scsi_merge.c .(which amounts to 204) > | > | Is this the limit of the maximum blocks we can > | read/write through a single scsi command, atleast > for > | the given kernel (2.4.29) ? How can I increase > | it?? > | > | I am on a P3 Dell poweredgde 2400 . > > Did you read the comment immediately above that > calculation? > > /* > * scsi_malloc() can only dish out items of > PAGE_SIZE or less, so we cannot > * build a request that requires an sg table > allocation of more than that. > */ > > so scsi_malloc() would need some reworking to handle > more. > > OTOH, it appears that this is all removed in > 2.6.10++, so moving to > 2.6.recent is probably your best choice. > > --- > ~Randy > - > To unsubscribe from this list: send the line > "unsubscribe linux-scsi" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at > http://vger.kernel.org/majordomo-info.html > __ Do you Yahoo!? Yahoo! Small Business - Try our new resources site! http://smallbusiness.yahoo.com/resources/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
increasing scsi_max_sg / max_segments for scsi writes/reads
Hi, I had posted a question on increasing the scsi read/write sectors per command. I figured out some of the things, but many questions still exist. I was wondering why the maximum writes I could get from a single scsi write command could never exceed 204 4096B segments . I traced it to : static const int scsi_max_sg = PAGE_SIZE / sizeof(struct scatterlist) in scsi_merge.c .(which amounts to 204) Is this the limit of the maximum blocks we can read/write through a single scsi command, atleast for the given kernel (2.4.29) ? How can I increase it?? I am on a P3 Dell poweredgde 2400 . Sai __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Maximum data read/writes per SCSI Command
Hi, I wanted to increase the number of sectors that could be requested/Written per SCSI READ(10)/WRITE command , and varying MAX_SECTORS in blkdev.h helped me to do it. However I could not request more than 256 sectors and could not write more than 1632 inspite of changing MAX_SECTORS to higher numbers. (request_bufflen stands still at 835584 for every command) Why is that? There is probably some other variable that should be varied. Please let me know. I am working on the UNH iSCSI initiator driver , and am on kernel 2.4.29 . Sai __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Increasing MAX_SECTORS in blkdev.h -2.4.29
Hi, I wanted to increase the number of sectors that could be requested/Written per SCSI READ(10)/WRITE command , and varying MAX_SECTORS in blkdev.h helped me to do it. However I could not request more than 256 sectors and could not write more than 1024 inspite of changing MAX_SECTORS to higher numbers. Why is that? There is probably some other variable that should be varied. Please let me know if anyone has an idea. I am working on the UNH iSCSI initiator driver , and am on kernel 2.4.29 . Sai __ Do you Yahoo!? Take Yahoo! Mail with you! Get it on your mobile phone. http://mobile.yahoo.com/maildemo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
