| Message ID | 1434450415-11339-8-git-send-email-dgilbert@redhat.com |
|---|---|
| State | New |
| Headers | show |
"Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > Useful for debugging the migration bitmap and other bitmaps > of the same format (including the sentmap in postcopy). > > The bitmap is printed to stderr. > Lines that are all the expected value are excluded so the output > can be quite compact for many bitmaps. > > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > include/migration/migration.h | 1 + > migration/ram.c | 38 ++++++++++++++++++++++++++++++++++++++ > 2 files changed, 39 insertions(+) > > diff --git a/include/migration/migration.h b/include/migration/migration.h > index 9387c8c..b3a7f75 100644 > --- a/include/migration/migration.h > +++ b/include/migration/migration.h > @@ -144,6 +144,7 @@ uint64_t xbzrle_mig_pages_cache_miss(void); > double xbzrle_mig_cache_miss_rate(void); > > void ram_handle_compressed(void *host, uint8_t ch, uint64_t size); > +void ram_debug_dump_bitmap(unsigned long *todump, bool expected); > > /** > * @migrate_add_blocker - prevent migration from proceeding > diff --git a/migration/ram.c b/migration/ram.c > index 57368e1..efc215a 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1051,6 +1051,44 @@ static void reset_ram_globals(void) > > #define MAX_WAIT 50 /* ms, half buffered_file limit */ > > +/* > + * 'expected' is the value you expect the bitmap mostly to be full > + * of; it won't bother printing lines that are all this value. > + * If 'todump' is null the migration bitmap is dumped. > + */ > +void ram_debug_dump_bitmap(unsigned long *todump, bool expected) > +{ > + int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS; > + > + int64_t cur; > + int64_t linelen = 128; > + char linebuf[129]; > + > + if (!todump) { > + todump = migration_bitmap; > + } Why? Just alssert that todump!= NULL? > + > + for (cur = 0; cur < ram_pages; cur += linelen) { > + int64_t curb; > + bool found = false; > + /* > + * Last line; catch the case where the line length > + * is longer than remaining ram > + */ > + if (cur + linelen > ram_pages) { > + linelen = ram_pages - cur; > + } > + for (curb = 0; curb < linelen; curb++) { > + bool thisbit = test_bit(cur + curb, todump); > + linebuf[curb] = thisbit ? '1' : '.'; Put 1 and 0? Why the dot? > + found = found || (thisbit != expected); > + } > + if (found) { > + linebuf[curb] = '\0'; > + fprintf(stderr, "0x%08" PRIx64 " : %s\n", cur, linebuf); > + } > + } > +} And once here, why are we doing it this way? We have find_first_bit(addr, nbits) and find_first_zero_bit(addr, nbits) and friends? Doiwg the walk by hand looks weird, no? Later, Juan.
* Juan Quintela (quintela@redhat.com) wrote: > "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote: > > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > > > Useful for debugging the migration bitmap and other bitmaps > > of the same format (including the sentmap in postcopy). > > > > The bitmap is printed to stderr. > > Lines that are all the expected value are excluded so the output > > can be quite compact for many bitmaps. > > > > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > > --- > > include/migration/migration.h | 1 + > > migration/ram.c | 38 ++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 39 insertions(+) > > > > diff --git a/include/migration/migration.h b/include/migration/migration.h > > index 9387c8c..b3a7f75 100644 > > --- a/include/migration/migration.h > > +++ b/include/migration/migration.h > > @@ -144,6 +144,7 @@ uint64_t xbzrle_mig_pages_cache_miss(void); > > double xbzrle_mig_cache_miss_rate(void); > > > > void ram_handle_compressed(void *host, uint8_t ch, uint64_t size); > > +void ram_debug_dump_bitmap(unsigned long *todump, bool expected); > > > > /** > > * @migrate_add_blocker - prevent migration from proceeding > > diff --git a/migration/ram.c b/migration/ram.c > > index 57368e1..efc215a 100644 > > --- a/migration/ram.c > > +++ b/migration/ram.c > > @@ -1051,6 +1051,44 @@ static void reset_ram_globals(void) > > > > #define MAX_WAIT 50 /* ms, half buffered_file limit */ > > > > +/* > > + * 'expected' is the value you expect the bitmap mostly to be full > > + * of; it won't bother printing lines that are all this value. > > + * If 'todump' is null the migration bitmap is dumped. > > + */ > > +void ram_debug_dump_bitmap(unsigned long *todump, bool expected) > > +{ > > + int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS; > > + > > + int64_t cur; > > + int64_t linelen = 128; > > + char linebuf[129]; > > + > > + if (!todump) { > > + todump = migration_bitmap; > > + } > > Why? Just alssert that todump!= NULL? 'migration_bitmap' is static to ram.c, so allowing NULL to get you a dump of the migration_bitmap means that if you call this dump routine from any error path you're debugging anywhere in qemu then you can dump the migration bitmap. e.g. I was adding calls to this in migration.c and migration/postcopy-ram.c in error paths I was trying to debug. > > + for (cur = 0; cur < ram_pages; cur += linelen) { > > + int64_t curb; > > + bool found = false; > > + /* > > + * Last line; catch the case where the line length > > + * is longer than remaining ram > > + */ > > + if (cur + linelen > ram_pages) { > > + linelen = ram_pages - cur; > > + } > > + for (curb = 0; curb < linelen; curb++) { > > + bool thisbit = test_bit(cur + curb, todump); > > + linebuf[curb] = thisbit ? '1' : '.'; > > Put 1 and 0? Why the dot? It's easier to see an occasional '1' in a big field of .'s. > > + found = found || (thisbit != expected); > > + } > > + if (found) { > > + linebuf[curb] = '\0'; > > + fprintf(stderr, "0x%08" PRIx64 " : %s\n", cur, linebuf); > > + } > > + } > > +} > > > And once here, why are we doing it this way? We have > > find_first_bit(addr, nbits) and find_first_zero_bit(addr, nbits) and > friends? > > Doiwg the walk by hand looks weird, no? Here's a compile-tested-only version using find_ - it's bigger, if you think it's better I can use this instead: void ram_debug_dump_bitmap(unsigned long *todump, bool expected) { int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS; int64_t cur; int64_t linelen = 128; if (!todump) { todump = migration_bitmap; } for (cur = 0; cur < ram_pages; cur += linelen) { int64_t curb; unsigned long next_bit; /* * Last line; catch the case where the line length * is longer than remaining ram */ if (cur + linelen > ram_pages) { linelen = ram_pages - cur; } if (expected) { next_bit = find_next_bit(todump, cur + linelen, cur); } else { next_bit = find_next_zero_bit(todump, cur + linelen, cur); } if (next_bit >= (cur + linelen)) { continue; } for (curb = 0; curb < linelen; curb++) { bool thisbit = test_bit(cur + curb, todump); fputc(thisbit ? '1' : '.', stderr); } fputc('\n', stderr); } } Dave > > Later, Juan. -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On (Tue) 16 Jun 2015 [11:26:20], Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > Useful for debugging the migration bitmap and other bitmaps > of the same format (including the sentmap in postcopy). > > The bitmap is printed to stderr. > Lines that are all the expected value are excluded so the output > can be quite compact for many bitmaps. > > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Amit Shah <amit.shah@redhat.com> Amit
"Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote: > * Juan Quintela (quintela@redhat.com) wrote: >> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote: >> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> >> > >> > Useful for debugging the migration bitmap and other bitmaps >> > of the same format (including the sentmap in postcopy). >> > >> > The bitmap is printed to stderr. >> > Lines that are all the expected value are excluded so the output >> > can be quite compact for many bitmaps. >> > >> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> >> > --- >> > include/migration/migration.h | 1 + >> > migration/ram.c | 38 ++++++++++++++++++++++++++++++++++++++ >> > 2 files changed, 39 insertions(+) >> > >> > diff --git a/include/migration/migration.h b/include/migration/migration.h >> > index 9387c8c..b3a7f75 100644 >> > --- a/include/migration/migration.h >> > +++ b/include/migration/migration.h >> > @@ -144,6 +144,7 @@ uint64_t xbzrle_mig_pages_cache_miss(void); >> > double xbzrle_mig_cache_miss_rate(void); >> > >> > void ram_handle_compressed(void *host, uint8_t ch, uint64_t size); >> > +void ram_debug_dump_bitmap(unsigned long *todump, bool expected); >> > >> > /** >> > * @migrate_add_blocker - prevent migration from proceeding >> > diff --git a/migration/ram.c b/migration/ram.c >> > index 57368e1..efc215a 100644 >> > --- a/migration/ram.c >> > +++ b/migration/ram.c >> > @@ -1051,6 +1051,44 @@ static void reset_ram_globals(void) >> > >> > #define MAX_WAIT 50 /* ms, half buffered_file limit */ >> > >> > +/* >> > + * 'expected' is the value you expect the bitmap mostly to be full >> > + * of; it won't bother printing lines that are all this value. >> > + * If 'todump' is null the migration bitmap is dumped. >> > + */ >> > +void ram_debug_dump_bitmap(unsigned long *todump, bool expected) >> > +{ >> > + int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS; >> > + >> > + int64_t cur; >> > + int64_t linelen = 128; >> > + char linebuf[129]; >> > + >> > + if (!todump) { >> > + todump = migration_bitmap; >> > + } >> >> Why? Just alssert that todump!= NULL? > > 'migration_bitmap' is static to ram.c, so allowing NULL to get > you a dump of the migration_bitmap means that if you call this > dump routine from any error path you're debugging anywhere in qemu > then you can dump the migration bitmap. e.g. I was adding calls > to this in migration.c and migration/postcopy-ram.c in error > paths I was trying to debug. ok. > >> > + for (cur = 0; cur < ram_pages; cur += linelen) { >> > + int64_t curb; >> > + bool found = false; >> > + /* >> > + * Last line; catch the case where the line length >> > + * is longer than remaining ram >> > + */ >> > + if (cur + linelen > ram_pages) { >> > + linelen = ram_pages - cur; >> > + } >> > + for (curb = 0; curb < linelen; curb++) { >> > + bool thisbit = test_bit(cur + curb, todump); >> > + linebuf[curb] = thisbit ? '1' : '.'; >> >> Put 1 and 0? Why the dot? > > It's easier to see an occasional '1' in a big field of .'s. ok. > >> > + found = found || (thisbit != expected); >> > + } >> > + if (found) { >> > + linebuf[curb] = '\0'; >> > + fprintf(stderr, "0x%08" PRIx64 " : %s\n", cur, linebuf); >> > + } >> > + } >> > +} >> >> >> And once here, why are we doing it this way? We have >> >> find_first_bit(addr, nbits) and find_first_zero_bit(addr, nbits) and >> friends? >> >> Doiwg the walk by hand looks weird, no? > > Here's a compile-tested-only version using find_ - it's bigger, if you think > it's better I can use this instead: > > void ram_debug_dump_bitmap(unsigned long *todump, bool expected) > { > int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS; > > int64_t cur; > int64_t linelen = 128; > > if (!todump) { > todump = migration_bitmap; > } > > for (cur = 0; cur < ram_pages; cur += linelen) { > int64_t curb; > unsigned long next_bit; > > /* > * Last line; catch the case where the line length > * is longer than remaining ram > */ > if (cur + linelen > ram_pages) { > linelen = ram_pages - cur; > } > if (expected) { > next_bit = find_next_bit(todump, cur + linelen, cur); > } else { > next_bit = find_next_zero_bit(todump, cur + linelen, cur); > } > if (next_bit >= (cur + linelen)) { > continue; > } > > for (curb = 0; curb < linelen; curb++) { > bool thisbit = test_bit(cur + curb, todump); > fputc(thisbit ? '1' : '.', stderr); > } > fputc('\n', stderr); > } > } > > Dave Reviewed-by: Juan Quintela <quintela@redhat.com> > > >> >> Later, Juan. > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff --git a/include/migration/migration.h b/include/migration/migration.h index 9387c8c..b3a7f75 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -144,6 +144,7 @@ uint64_t xbzrle_mig_pages_cache_miss(void); double xbzrle_mig_cache_miss_rate(void); void ram_handle_compressed(void *host, uint8_t ch, uint64_t size); +void ram_debug_dump_bitmap(unsigned long *todump, bool expected); /** * @migrate_add_blocker - prevent migration from proceeding diff --git a/migration/ram.c b/migration/ram.c index 57368e1..efc215a 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1051,6 +1051,44 @@ static void reset_ram_globals(void) #define MAX_WAIT 50 /* ms, half buffered_file limit */ +/* + * 'expected' is the value you expect the bitmap mostly to be full + * of; it won't bother printing lines that are all this value. + * If 'todump' is null the migration bitmap is dumped. + */ +void ram_debug_dump_bitmap(unsigned long *todump, bool expected) +{ + int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS; + + int64_t cur; + int64_t linelen = 128; + char linebuf[129]; + + if (!todump) { + todump = migration_bitmap; + } + + for (cur = 0; cur < ram_pages; cur += linelen) { + int64_t curb; + bool found = false; + /* + * Last line; catch the case where the line length + * is longer than remaining ram + */ + if (cur + linelen > ram_pages) { + linelen = ram_pages - cur; + } + for (curb = 0; curb < linelen; curb++) { + bool thisbit = test_bit(cur + curb, todump); + linebuf[curb] = thisbit ? '1' : '.'; + found = found || (thisbit != expected); + } + if (found) { + linebuf[curb] = '\0'; + fprintf(stderr, "0x%08" PRIx64 " : %s\n", cur, linebuf); + } + } +} /* Each of ram_save_setup, ram_save_iterate and ram_save_complete has * long-running RCU critical section. When rcu-reclaims in the code